0:00

You do anything to keep your vehicle happy.

0:02

Let's make sure it stays running smoothly. With

0:04

eBay Guaranteed Fit, you'll find the right

0:07

parts that fit your vehicle the first time. From

0:09

air filters to headlights to batteries and

0:11

bumpers. When you see the green check, you

0:13

know that part will fit. Get the right parts

0:16

at the right prices. At theebamotors.com,

0:19

let's ride. Eligible items only,

0:21

exclusions apply.

0:23

As if the McChrissy

0:25

couldn't get any better. Bacon

0:27

and Ranch just entered the chat. The

0:30

Bacon Ranch McChrissy, available

0:33

and participating with Donald's for a limited time.

0:39

You and Betty and the Nancy's

0:42

and Bill's and Joe's and Jane's will

0:44

find in the study of science a

0:46

richer, more rewarding life.

0:50

Welcome to Inquiring Minds. I'm

0:53

Andrea Viscontis. This is a podcast

0:55

that explores the space where science and society

0:57

collide. We want to find out what's true, what's

0:59

left to discover, and why it matters.

1:11

We're coming up to the 400th episode

1:14

of this podcast. And so I'm revisiting

1:17

some of my favorite topics with new

1:19

guests, sometimes with a co-host,

1:22

with multiple guests.

1:24

And so this week I thought it would be appropriate

1:26

to talk about a major scientific

1:28

discovery. Physics is definitely

1:31

not my forte, but I always love

1:33

talking to experimental physicists or theoretical

1:36

physicists, not just because

1:38

they helped me feel insignificant,

1:42

but also because they put things into perspective.

1:44

All of a sudden when

1:46

you're talking about discovering

1:48

a whole new way of powering our

1:50

world, or our place

1:53

in this vast universe, the everyday

1:55

problems that I'm facing seem less

1:57

important. So this week

1:59

I- the pleasure of talking to two

2:02

physicists, yep two at the same

2:04

time, both from Lawrence Livermore National

2:06

Labs. And they were part of the team

2:09

that had this huge breakthrough back in December 2022

2:12

when essentially in a series of experiments

2:15

they showed that fusion is actually

2:17

a viable potential energy source. Sabrina

2:20

Nagel is a group leader in the physics division

2:23

at Lawrence Livermore National Labs and she's the

2:25

lead scientist for the National

2:27

Ignition Facilities Dynamic X-ray

2:29

detectors group. And then Dr. Matthias

2:31

Hohenberger is an experimental scientist

2:34

and group leader working on inertial confinement

2:36

fusion at the NIF, at the Lawrence Livermore

2:38

National Labs. He's been working on performing

2:40

experiments in the pursuit of, and now

2:43

on the accomplishment of, fusion

2:45

ignition for the last 13 years.

2:51

Sabrina and Matthias, welcome

2:54

to Inquiring Minds. I'm so excited to talk

2:56

to you. Well, thank you very much for having us.

2:59

Yeah, thank you for having us. It's exciting. So

3:01

let's start with, first

3:03

of all, in terms of your respective roles,

3:06

can you each just tell me, maybe we'll start with Sabrina, what

3:09

your roles are on the sort of grand

3:12

thermonuclear

3:13

fusion project? Sure.

3:15

So yes, I am

3:19

one of the scientific leads in

3:22

developing some of the diagnostics, the

3:24

experimental diagnostics for the

3:26

National Agression Facility. And we have optical

3:29

diagnostics, nuclear

3:31

or particle diagnostics, as well as x-ray diagnostics.

3:34

And so I'm kind of heading a part of a

3:36

co-head, so to speak, for

3:38

developing some of those systems.

3:42

And as, yeah,

3:44

I've been working on this for over 10 years

3:46

now. And it's great to see

3:48

that we're getting

3:50

exciting results. And yeah, as

3:53

you might imagine, the diagnostics

3:56

are what measures

3:59

what's going on.

4:00

in the experiments and helps

4:02

us tweak and change

4:04

the input parameters so that we were

4:06

able to achieve ignition. All right.

4:09

And so, Mathias, are you the one that pushes the button? Is

4:12

there a big red button that you push? Unfortunately

4:15

not. That would be so exciting. No,

4:18

I'm what's generally referred

4:20

to as an experimental physicist. So I'm

4:24

one of the many people that would

4:27

tell the facility operators how

4:29

to set up experiments, what

4:32

we want to measure, how to set up the diagnostics

4:34

that Sabrina and her team has developed,

4:37

and what it is that we're trying to do in

4:39

this particular experiment. And

4:41

so I'm doing experiments in the ICF,

4:43

the National Confine Refusion Program,

4:47

and I'm also a group leader for inclusion

4:49

in stagnation physics, which means the

4:51

people in my group also do experiments in this area.

4:54

So let's talk about fusion. And just

4:56

for our listeners who maybe are

4:58

not as familiar, what

5:00

exactly are we talking about here? What's

5:03

the fundamental

5:04

idea behind it? So

5:07

fusion is a nuclear

5:09

process, which means it's happening with

5:12

the nucleus of the atom, which is the heavy part in

5:14

the center that's surrounded by electrons.

5:18

It basically changes the configuration of the

5:20

nucleus. There's two main ways of doing this.

5:23

One is fission, that's what most people are familiar with, and

5:25

the other one is fusion.

5:26

Fission is the part where you

5:28

split up the nucleus into smaller

5:31

parts, and then fusion is the

5:33

opposite process where you take two light

5:36

elements, two light nuclei,

5:38

and push them together hard

5:41

enough that they stick together because they don't want to be together,

5:44

that they stick together and form a heavier.

5:47

And so in the fusion process here,

5:49

we're taking two deuterium

5:52

and tritium ions. That's basically

5:54

hydrogen, hydrogen is the lightest element we had with

5:57

a few extra neutrons and we're squeezing them.

6:00

together under very intense pressures

6:03

and temperatures. And then when they stick

6:05

together, they form helium, which is the second lightest

6:07

element that we have. And

6:10

when we weigh the helium

6:12

atom at the end, it's actually lighter

6:14

than the sum of its part, the

6:16

sum of the elements that we squeeze together. And

6:19

by Einstein's

6:19

equation,

6:22

energy equals mass times

6:24

the speed of light square, that means that

6:27

difference in mass has to go somewhere. And that's

6:29

the energy that is being released as heat

6:32

is it? So that's what fusion. And

6:34

so the ultimate idea here, potentially

6:37

in terms of an application, is that you could

6:39

create a lot of energy

6:41

with this process. And it

6:44

how, you know, can you tell us a little bit about so

6:46

like the kind of grand hundred

6:48

years from now vision, or

6:50

whatever that is, maybe it's five years from now, I don't know,

6:54

that you know, you could capture that energy and

6:56

use it and is it is it how is it better

6:58

than

6:58

some of the other energy sources that we have today?

7:01

So the fusion energy

7:03

is basically held

7:07

to promise of a clean, carbon-free,

7:11

robust energy source for

7:14

everyone. And basically,

7:16

it's also clean in

7:19

the sense of that it doesn't produce

7:21

radioactive waste with long half

7:23

nights.

7:25

And then it is not reliant

7:29

on the sun being out or the

7:32

wind blowing for us to have

7:34

it. You can have it at the push of a button, hopefully

7:37

in the future.

7:38

And so with that, and

7:41

then the fuel that we need for it is

7:43

also very fairly abundant. So hydrogen isotopes,

7:47

you can get them from seawater.

7:49

And so they're fairly readily available

7:52

for people to use.

7:53

Yeah, so maybe the vision in the future would be that

7:56

you could use some amount of seawater and

7:58

create an abundant energy.

8:00

source that could cleanly

8:02

power our lives without

8:04

the danger that some of the other power

8:07

sources have. Is that right? That

8:09

is right. It doesn't produce greenhouse

8:13

gas emissions. It

8:14

doesn't produce these long-lived half-life for

8:17

radioactive isotopes that

8:19

people are rightly worried about. You

8:21

don't have things that are still radioactive

8:24

in 20,000 years.

8:26

And also it doesn't have

8:28

this runaway reaction process that can

8:31

happen immediately a reactor like Chernobyl

8:33

just cannot fundamentally happen with

8:36

the reaction,

8:36

with fusion reactions. So I want

8:39

to learn a little bit more about like, you

8:41

know, what the actual

8:43

experiment or what the work is like. So first

8:46

of all, you've got these tiny

8:48

atoms,

8:48

right? So how, I mean, where

8:50

do you get them from? How do you know they're there?

8:53

I mean, this is such a, having the two of you here

8:55

is such a gift because I feel like, you

8:57

know, you can, you can teach me a lot about

9:00

sort of how you're detecting that they're actually there, that

9:02

it's actually going and how you put it all together.

9:04

So can you just walk me through

9:06

like the steps of,

9:08

you know, one of these experiments?

9:10

Okay, so the fundamental

9:12

target is basically

9:15

a small capsule. It's about

9:17

two millimeters in diameter, and

9:20

it's made out of diamond. In

9:23

that hollow capsule, in that sphere,

9:25

is a cryogenic layer of deuterium

9:28

tritium ice. Deuterium tritium are

9:30

these heavy hydrogen isotopes.

9:32

There's a very thin layer of

9:34

ice, so it's like 14 Kelvin or so, so

9:37

very close to absolute zero. But like,

9:39

do you put that in there? Like do you have the capsule,

9:41

you have like a whole bunch of these diamond capsules and you

9:43

stick a little bit of. Yeah. So

9:47

the capsule has a little filter.

9:49

The filter was two microns in diameter. So

9:51

that's 50 times smaller than the width of a

9:53

hair. And so that you, you basically

9:55

pump gas, deuterium, deuterium gas in

9:57

there. And then you cool it down and you...

10:00

form this layer in a very complicated, intricate

10:02

process that,

10:03

in fact,

10:05

no, very little about there are experts to

10:07

do this. And then, so

10:10

that's your target, that contains the fuel. And

10:12

this little pellet sits inside a whole

10:15

realm, which is about, it's a

10:17

little, a gold cylinder

10:19

about a centimeter in size.

10:22

And so what happens now, we have this massive

10:24

laser facility, the National Ignition Facility, It

10:27

has 192 laser beams, and we take these

10:30

laser beams, it's the most powerful laser in the world,

10:33

we take these laser beams and we

10:35

focus them into that tiny target. Laser

10:37

beams, half at the top, half at the bottom, 96 beams

10:39

on each side. They're focused through

10:41

a little hole in the cylinder

10:44

onto the walls of the cylinder, and

10:46

in a very short time, about 10 nanoseconds

10:48

or so, we

10:50

put 2 megajoules of energy

10:52

into the cylinder.

10:54

And so that laser energy

10:57

heats up this little cylinder to ridiculous

11:00

temperatures.

11:02

Basically it gets an

11:04

incredibly hot oven of about 3 million degrees.

11:07

And that then starts ablating

11:10

the outer wall

11:12

of the capsule that sits in the center. Because

11:14

it gets so hot, right, the things just sort of fly apart. And

11:16

because the stuff on the outside of the capsule

11:19

flies apart,

11:20

the stuff on the inside gets compressed.

11:23

reaction and reaction via

11:26

neutron. It's the same way that

11:28

a rocket works. It pushes a lot of stuff out at one

11:30

side and the rest of the rocket goes up.

11:33

And so that's how this thing gets compressed.

11:35

And so the

11:37

thing basically implodes, that's what

11:39

we call it, and the center

11:41

of that capsule, the DT, gets

11:44

to a pressure of about 500 gigabars,

11:47

which is 10 times

11:49

higher than the sun, and about 150

11:51

million degrees, which

11:54

is also about 10 times hotter than the sun. And

11:57

that is the conditions that you need but these three

11:59

reactions. take place. Okay,

12:02

so now I have a sense of like, you know,

12:04

there's this little tiny thing in this big room

12:07

with all of these lasers pointed at it. It

12:09

creates, you know, this big

12:12

sort of almost like I think of it as maybe like

12:15

a little explosion when all these lasers are hitting

12:17

it and that causes the pressure

12:19

that puts these

12:21

two atoms together. So

12:24

Sabrina, now I'm assuming that

12:26

this is maybe where you come in in terms

12:29

of making sure this all happened the way it was supposed

12:31

to

12:31

or, you know, what, so, so

12:33

what happens next? That's right. I

12:36

mean, in addition to what, to the experimental diagnostics,

12:40

I should add, like there's also already diagnostics

12:42

going on at the beginning of the experiment

12:44

before the

12:44

experiment actually happens while this ice

12:47

layer is being grown. There's already X-ray

12:50

radiography of that capsule to

12:52

make sure that the layer is very uniform

12:54

and thicknesses and it's growing as it's

12:56

supposed to be growing and that we know that we have an

12:59

ice layer.

12:59

And then there's alignment

13:02

systems, etc. So there's a lot of diagnostics

13:04

that are

13:05

facility diagnostics that are on every

13:07

experiment that we do.

13:09

And that tell

13:11

us that the targets in the right place, that

13:14

the lasers are hopefully going to give you the right energy,

13:16

etc.

13:17

And then

13:20

when the laser fires and that system

13:22

heats up and and everything. So we have

13:25

different diagnostics

13:30

and the ones that in particular

13:32

for these ignition

13:35

type experiments, the ones that are telling

13:37

us that we got the

13:39

neutron yield or the energy out that

13:41

we expected or

13:43

the number of the three megajoules

13:45

out, above three megajoules out, we

13:47

got that mainly from the neutron detectors.

13:50

And so those are basically measuring the

13:53

in this fusion reaction that Matthias

13:55

was talking about earlier, where we diffuse

13:57

these deuterium and tritium isotopes.

14:00

and put them in, they make a helium

14:02

and a neutron. So the helium generally

14:04

stays in this hotspot or this

14:07

hot gas, continuing the

14:09

heating because it's such a big particle.

14:11

And the neutron that we get out is fairly high energy,

14:14

about 14 mV, and that escapes.

14:16

And so we can measure those escaping

14:18

the interaction. And basically

14:21

we count neutrons. And that's

14:23

how we know how much energy we got. So

14:25

there's a...

14:26

because the energy that comes out

14:28

of these reactions is known. And

14:31

so we count

14:33

neutrons to know how much energy we got out. And

14:37

that's fairly simple. And in addition to that,

14:39

we also try and look at the

14:41

X-rays, so this hotspot that's very hot

14:44

now, and it's hotter than

14:46

the center of the sun. And

14:49

so it emits this bright

14:52

light in X-rays, and

14:55

that allows us to image them. We're

14:57

using X-ray cameras. Okay, so

14:59

this whole process happens. How long does it take?

15:02

Like is this something that happens in like

15:05

a couple nanoseconds, or

15:07

is it like,

15:07

you know, you get the thing

15:09

going and it takes three days, and

15:12

then you get your result? So the

15:14

experiment is like in the blink of an eye, right?

15:16

So the, as Matthias mentioned,

15:18

the laser that drives it is about 10 nanoseconds

15:21

long, which is about

15:23

the time that it takes

15:24

light to travel about 3 meters

15:26

or just under 10 feet. And

15:29

then the interaction itself where the fusion

15:31

happens, that time scale is on the order

15:34

of 100 picoseconds. So

15:37

that is the time it takes

15:38

to travel about 3 centimeters, a little

15:40

bit more than an inch. And then

15:42

for spatial scales, we

15:45

mentioned that this experiment sits in the center of this

15:47

big chamber. And

15:49

the chamber, this vacuum chamber has

15:51

a diameter of 10 meters. And

15:53

so we have to, at that

15:56

center is this one centimeter

15:58

large pore realm.

16:00

And so we have to align the lasers

16:02

into that.

16:03

And then the compression of the capsule

16:06

that is starting out at the two millimeter scale,

16:08

which is about a peppercorn size, we

16:11

have to compress that,

16:12

or that gets compressed to the order of

16:15

the width of a hair, so about 50 microns.

16:17

And so that's the scale that we're kind of trying to measure, like

16:19

the 50 micron scale width,

16:22

and we're trying to measure that with some resolution,

16:24

so our resolution has to be below

16:26

the 10 micron

16:29

resolution.

16:31

And yeah, and then in addition,

16:33

the whole experiment because so if

16:35

you think about it, the two millimeter pellet

16:39

compressing to the 50 micron hotspot,

16:42

basically,

16:42

that's similar to trying to compress

16:44

uniformly compress a basketball to

16:46

the size of a P. And

16:49

so that's kind of, and we're trying to do this

16:51

uniformly

16:51

so that It doesn't

16:53

burst out at one point and it won't get the heat

16:56

and the density that you need in the core

16:58

to get the fusion going. SL.

17:00

Sabrina talked about neutrons a lot and we haven't

17:03

actually mentioned that yet. So

17:07

when we fuse the deuterium and the tritium together,

17:09

so we create helium,

17:10

but then we also create a whole bunch of other stuff. We create

17:13

a lot of radiation,

17:14

x-rays are flying out, we can see those, we

17:16

can measure those, we create

17:19

particles as well that we can see neutrons

17:21

predominantly.

17:22

And so that is the

17:24

neutrons that are being emitted at

17:26

a specific energy, that is the signature of fusion

17:28

reactions taking place.

17:30

And it is one of our key ways

17:32

of measuring the performance of this experiment.

17:36

So we essentially count the number of neutrons

17:38

that we're getting out, and that tells

17:40

us exactly about

17:42

conditions in the hotspot. You

17:44

can measure the velocity of the neutrons essentially, that tells

17:46

you about the temperature, how many neutrons

17:49

did you get out, that tells you about

17:50

how good was your reaction, how efficient

17:53

was your reaction.

17:55

And so that's why Sabrina was talking

17:57

about

17:57

measuring neutrons. signatures.

18:00

Where is the energy

18:02

that then ultimately like let's say

18:05

this goes to scale that we would use

18:07

to power it? Is it in the release

18:09

of the neutrons? Like what is

18:12

it that ultimately we would want to capture and use

18:14

to power our

18:15

refrigerator or

18:17

whatever? So

18:20

the funniest thing is that

18:23

we do all these really amazing

18:25

things and then at the end

18:27

of the day, we basically boil the kep.

18:30

So that's how a fission reactor works

18:32

as well. Right? You have these fission

18:34

reactions that creates heat,

18:36

which then essentially boils water and

18:38

without water you dry the turbine and

18:40

that generates electricity for the grid.

18:43

And you would do exactly the same thing with a fusion reactor,

18:45

which is, I think is hilarious

18:48

because we have a state of the art scientific

18:50

understanding. And then we do the same thing that

18:52

humans have been doing for, I don't know, millions

18:55

of years.

19:26

When you're behind the wheel,

19:28

it's okay to rock out to your music,

19:31

but it's not okay to interact with your phone

19:33

screen and electronic devices while

19:35

driving. In most cases, anything

19:37

more than a single touch or swipe is

19:40

against the law. That means no

19:42

texting, no typing, no scrolling,

19:45

no shopping, no browsing. If

19:47

an officer sees a violation, they can

19:49

pull you over. So remember,

19:52

Ohio, phones down. That's

19:54

the law.

20:00

get any better. Bacon and Ranch

20:02

just entered the chat. The

20:05

Bacon Ranch McChrispy, available

20:07

at participating McDonald's for a limited time.

20:19

So, um, there was a lot of press,

20:22

uh, a little while ago about, you know, it finally

20:24

being successful. Can you walk me through

20:26

like how many times was it unsuccessful

20:29

or was it like Like this was actually the

20:31

10th successful run because that's what you need

20:33

in order to publish a paper. Like what sort

20:35

of like the, what was it, or was it like,

20:37

oh, finally it worked after the hundredth time that

20:40

it didn't work. Um, what, what, what, how did

20:42

this discovery kind of come about?

20:44

So the,

20:46

the important takeaway is that this

20:49

is, this has been, uh, about

20:51

six decades in the making. Um,

20:53

so there's been a countless number of scientists

20:55

and engineers that have been working on

20:57

this all over the world. This is

20:59

a US-only project.

21:02

It took a lot of learning

21:04

to get to the point where we are today. I

21:07

don't know how many times have we tried it and failed. That's

21:10

a very difficult question to answer, but 60 years.

21:14

It took all this time to understand

21:16

the limitations

21:19

of the laser capabilities that

21:21

we had 50 years ago or so,

21:23

what we needed to do better, how smooth

21:26

this laser have to be, how uniform does the

21:28

compression have to be?

21:28

How perfect do these targets have to be? What

21:31

are the processes that

21:33

are going on at these very, very extreme conditions

21:36

that we're creating?

21:38

Temperatures and pressures like

21:40

the sun, and

21:41

how do we overcome these instabilities?

21:45

Ultimately, it's a race. If

21:47

you make something very, very hot, it doesn't

21:49

want to stay hot. It wants to

21:51

become cold, part of boiling water

21:53

out, it gets cold again. And

21:56

so the race is to compress

21:59

it fast. of keep the reaction

22:01

going for long enough before the

22:03

whole thing falls apart again, because that's what it

22:05

will do. That's why it

22:07

can't have this runaway reaction. It wants

22:10

to stop again.

22:11

And so being able to control that reaction

22:14

at a sufficient level, that's what took so

22:16

long.

22:17

And to the outside, this looks like a breakthrough,

22:19

and it is,

22:21

but really it's a series

22:23

of incremental steps over several

22:25

decades.

22:27

And really within the program,

22:29

people that are close to these experiments, we've

22:31

known that we're really, really close to getting this

22:34

for the last couple of years. There's

22:37

always an element of

22:38

surprise when it actually does

22:40

happen. But

22:43

we've known that we've been close for a

22:45

while. And

22:47

actually, I want to point out how incredible

22:50

the

22:50

requirements are. So for example,

22:53

the

22:53

capsules that we're shooting are

22:56

just marvelous

22:58

products of engineering. For example,

23:00

they're so smooth, so these are about two millimeters

23:03

in diameter, they're

23:04

smooth to about three

23:06

to four nanometers. And

23:08

just to put that in perspective, if you were to blow

23:10

that capsule up to the size of the earth, the

23:13

biggest hill you'd see would be about 100

23:16

feet. That's

23:18

how smooth they

23:19

are. And that's what's required

23:21

for this implosion to be clear,

23:24

because otherwise what happens is you get basically

23:26

jets forming and material being ejected

23:29

into the hotspot

23:30

and you don't want that because it disturbs the reaction.

23:33

They're not entirely perfect. One of the issues

23:35

we've been having over the last couple of years is that there

23:37

are what we call

23:39

defects in these capsules. There are little

23:42

pits or maybe little bubbles, little voids

23:44

in the wall of the target, things

23:46

like that. some high-set materials

23:48

that you don't want tons or something like that

23:51

at a place where you don't want it. All of that is

23:53

important. All of that will make the implosion

23:56

of fall

23:57

less good. And so that's

24:00

part of the process of learning how to do this right.

24:02

Sabrina, anything you want to add in terms

24:05

of what Mathias was just talking about?

24:07

Yeah, I mean, this is, I guess, we've

24:10

had a lot of fusion reactions in

24:12

the lab, right? I mean, we've been counting, we

24:14

know how to fuse deuterium

24:16

and tritium, but that has happened.

24:20

It's the amount of energy that

24:22

we get out, so the amount of fusion reactions

24:24

that we see.

24:25

And as Matthias mentioned,

24:28

the first time that we

24:30

get more of the fusion energy

24:32

out than we put in, that's the real thing

24:35

that happened in December. We were really

24:37

close before then on a number of experiments

24:40

that were in kind of what we called the burning regime,

24:42

which is very

24:44

close. And you could, from that step,

24:47

say, okay, we're getting there and

24:49

it's just a matter of time. And

24:51

what happened was we basically got a little

24:53

bit more energy. we made the capsules, I think,

24:55

a little bit thicker, a little bit more

24:57

robust, and that pushed us over the edge, basically.

25:01

And so how replicable is it now?

25:03

Like, do you feel like, OK, well, now we know exactly what

25:05

to do, and if we did it again tomorrow, it

25:07

would work exactly the same way? Or is it

25:09

more like, well, you know, we were kind of lucky

25:11

because we didn't have any tungsten on that particular

25:13

part of the capsule that time.

25:16

But like, you know, I think about like how hard it

25:18

is to put one of those, you know, glass

25:20

protectors on an iPhone, like one of those bubbles

25:22

come, you know, it's super annoying. like.

25:27

Yeah, so

25:29

like talking to target fabrication, they're

25:31

very fairly confident that they

25:32

can create, recreate like

25:35

capsules with that quality again.

25:38

And same for the laser, they are very confident

25:40

that they can deliver

25:43

same type of laser pulse shapes. So

25:45

from that perspective, we are very confident

25:46

that we could reproduce

25:48

it as a team, right? So there's

25:51

definitely plans to do that at least one time this

25:53

year, probably maybe a couple

25:56

of times this year.

25:57

And you know, what is the major hurdle?

26:00

in terms of just doing it over and over again. Like

26:02

what is it? It sounds expensive.

26:03

You've got a lot

26:05

of person power, but like, you know,

26:07

so like, why aren't you doing it every

26:09

day? Like, you know, what's the... Yeah,

26:12

it's a little bit of people power. Then the other thing

26:14

is that the facility is not just used

26:16

for this. There's also other

26:18

shots on there. So these are not the only

26:20

shots. We have like 400 shots a year roughly

26:22

on the facility and ignition

26:25

shots or like ICF related shots,

26:28

especially these more

26:31

involved experiments, they're on

26:33

the order of every two weeks to four

26:36

weeks. So maybe once a month, really,

26:38

the high kind

26:40

of on that time scale. But

26:42

the other limiting thing is,

26:44

yeah, you have to like after these shots,

26:47

you have to stay out times for personnel

26:49

safety,

26:50

et cetera, because there is some

26:52

activation

26:54

from the neutrons short-lived, but

26:56

you don't want to get in there too quickly.

26:59

And then there's some time that we have

27:01

to do data collection as well and

27:03

the laser cannot, I think,

27:05

at this point, shoot at

27:08

these high energies

27:09

on a high

27:13

repetition rate for us, it's like once a day. But we

27:16

can't really shoot at that rep

27:19

rate for the laser at this point. Because this was,

27:21

and I think, yeah, the laser

27:23

was built in the,

27:25

on 80s, 90s laser technology.

27:28

So you could make it more efficient

27:30

nowadays, but that's when the facility was,

27:33

or the technology was established

27:34

for this technology, for this facility.

27:37

Okay, so now that you've proven

27:40

that it's possible, you got more energy than you

27:42

put in, what are the next

27:44

steps that have to be done before

27:46

this is going to be, you know, an option

27:48

that people can use?

27:50

Do we know what those next steps are? Is there like

27:53

a clear trajectory or is it still

27:54

like, you know, unclear? Well,

27:58

I'd say yes and no. certainly some things

28:01

that we know that need to be done.

28:04

It's certainly not at the point where you expect

28:06

a future power plant to happen tomorrow.

28:09

I think

28:10

what we did demonstrate is that

28:12

the science works. You can

28:14

get more energy out of the system than

28:16

you put in, and that's important because

28:19

it moved the whole thing from a science problem

28:21

to an engineering problem.

28:23

But really, so we put two megages of energy

28:25

in. We got three megajoules of fusion

28:27

energy out, but

28:29

that's really not good enough for a power plant.

28:31

You really want something like, say, 50, maybe 100

28:34

megajoules, so much, much higher efficiency

28:37

than we demonstrated. The other

28:39

thing you want to do is you want to be able to shoot this 10

28:41

times a second, which with the

28:44

laser that we have here is not possible.

28:46

The targets are much too complicated to do that.

28:49

So there's a lot of problems

28:52

that have to be simplified, a lot of things that have to simplified

28:54

before we can do this.

28:56

And then it's also not clear

28:58

what the best approach is to a power plant.

29:01

So we use lasers to compress these targets.

29:03

That's not the only approach that you can use. It's

29:06

the one that we're doing and it's the one we understand

29:08

the best, obviously. But there are other ways to do

29:10

this. There you can use magnetic fields

29:12

to confine the hot dense plasma. There's

29:15

things like proton

29:18

ignition where you use the accelerated protons

29:20

to hit a little capsule and make it hot that way.

29:23

So there may be other approaches that may or

29:25

may not work better and there's

29:28

work that needs to be done to figure out what's the best approach,

29:30

what's the most viable, commercially

29:33

approachable, the

29:35

best way to approach this commercially.

29:37

And so I think we're still certainly

29:40

years away from this, from having something

29:42

like a fusion power plant. But

29:44

I like the comparison to the Wright

29:46

Brothers

29:47

demonstration of flight in 1903 because

29:50

they flew 100

29:51

feet or so, which, you know,

29:53

that's not useful. But the

29:55

implications were enormous. And now of course,

29:57

flight is everybody.

30:00

uses flights for transporting

30:02

cargo and people and

30:04

defines society in the event today.

30:06

Yeah, in addition to that, I mean, just to note

30:08

for this shot, ignition shot, the

30:11

actual energy I think that NIF took from the grid

30:13

in order to achieve the shot was 300 megajoules. So

30:16

that went into two megajoules

30:18

of the lift of the laser, which then got

30:20

one and a half out. So the laser that drives the

30:22

target was the two megajoules and

30:24

then about three megajoules out of

30:26

fusion energy.

30:27

So that's where the one and a half times comes from. So

30:29

we're not wall pluck even,

30:32

we're not at that point. And

30:34

NIF wasn't really built to do this. This is a science

30:37

facility. So this was shown

30:40

to prove the principle. And

30:43

so yeah, we would have to have

30:45

way more efficient lasers. And

30:47

I think nowadays the laser

30:49

technology also is like, the

30:52

efficiency I think is coming to 20% wall

30:54

pluck efficiency for laser technology. So

30:57

that's a lot better than the NIF can do at this point.

31:00

And the repetition rate for these high-energy lasers

31:03

has gone up as well, which is something that you

31:04

would need for a power plant, right? You would need

31:07

a high repetition rate. You have to have this

31:09

kind of type of interaction every second.

31:11

And so you need a very robust

31:14

and easy to manufacture targets for that. And

31:16

so the

31:16

approach that NIF is taking might not

31:19

be the approach that a power plant has

31:21

as well. But there's currently

31:23

people looking at that. What would be the efficient

31:25

way to

31:26

do? But you still think that in the power

31:28

plant, it would be some version of

31:30

lasers shooting a small thing

31:34

or maybe a mid-sized thing that

31:37

would still be the kind of conceptually

31:39

the same idea?

31:40

If we were to design it, yes.

31:45

And then the magnetic confinement people

31:47

would say

31:47

it's more like a tokamak. Got it.

31:50

It's like more that magnetically confined doughnut. And

31:53

then some other, yeah, so it depends

31:56

on who you talk to, I think.

31:57

that different technologies have different...

32:00

risks, different technological risks

32:02

that need to be addressed, I think, at

32:03

this point. And there's people both

32:05

in the industry as well as in laboratories and

32:07

in national laboratories working on it and

32:10

kind of collaborating on it as well. Yeah,

32:12

so I was going to ask about- But they're all doing the same thing. Sorry.

32:15

Yeah. Like, what is the

32:17

industry's reaction to this? Are they all

32:19

kind of now rushing in to be

32:21

the first to, you know, kind of create

32:24

a commercially viable

32:26

version of this, or are they

32:28

still sitting back on the sidelines, letting

32:30

the scientists figure out and make

32:32

it more efficient?

32:34

There has been a lot

32:36

of commercial interest. There are a number

32:39

of companies, startups,

32:43

some of them have been around for a couple of years now,

32:45

that are

32:46

trying to get a foot in this

32:48

commercial space and working on potential

32:51

viable plant designs.

32:54

the recent

32:56

results that we've had in 2021,

32:58

we demonstrated a megajoule of yield.

33:00

In

33:01

December 22, we demonstrated

33:03

a gain of one and a half, three megajoule

33:06

yield.

33:06

That has certainly invigorated the space,

33:09

but it's been pretty active for a couple of years

33:11

now.

33:12

I think more investment has probably

33:14

been made in the magnetically

33:16

confined, if you will, approach the

33:18

Tokamak. But

33:21

yeah, there's a lot of activity and there's a lot of money from

33:23

private investors that has been pumped into this.

33:25

Absolutely. So when

33:27

you look to the future, I mean, I know you have at

33:30

least one child, if not more than one child,

33:32

and you think about sort of how, you know,

33:35

we're

33:35

facing some major climate

33:38

issues, some major environmental

33:41

issues. How do you feel

33:43

like, you know, in terms of, do you think

33:45

that this ultimately is going to be the

33:48

answer or is it one of the answers

33:51

or like how do you feel in terms of

33:54

what the future looks like when it comes to

33:56

energy. So

33:57

yeah, so we have two children and yes.

34:00

We are very hopeful,

34:02

of course, especially now with this ignition result,

34:04

that a fusion power plant

34:06

is

34:07

in their lifetime

34:09

at least, something that is

34:12

viable and comes on and

34:14

helps with the

34:15

energy security for all

34:18

countries as well. And

34:22

in the meantime, the solar

34:24

and wind power, but again, these might be dependent

34:27

on where you live and storage

34:30

capabilities as well, right? It's

34:33

not the switch of a button

34:35

sometimes. If the sun doesn't shine in

34:37

your area or you have very

34:40

short days, you have to be very limited

34:42

in that.

34:43

I think

34:44

we have to be realistic about the

34:46

timescales. I mean,

34:49

I'm certainly not an expert in climate science,

34:51

but

34:52

I would say we probably have to act

34:54

faster here than

34:56

we will be able to act with fusion

34:58

power.

34:59

I certainly think and hope that

35:01

it

35:01

will be one of the solutions in the

35:03

future, but

35:04

we should not

35:06

rely on it and say, all right, we'll

35:09

just wait till fusion is a viable

35:11

power source and then we'll go from there. That's

35:13

probably going to be the

35:15

wrong approach. So I

35:17

have one last really

35:19

stupid question that probably you're

35:22

going to be like, that's for an

35:24

astronomer, which is,

35:27

you know, NASA a few weeks back

35:30

told us there is a part of the sun that

35:32

kind of broke off, but don't worry, everything's

35:34

fine. I've been dying

35:37

to ask a physicist, it seems like somebody who's

35:39

like creating little tiny suns

35:42

in their laser beam

35:45

world might be the person to ask, should

35:48

we not be worried about this or

35:50

what's going on there?

35:52

unlikely that that's going to create fusion. So

35:57

the sun, as you mentioned, I don't think we mentioned

35:59

it yet.

36:00

But yeah, the Sun is a fusion

36:02

power plant, right? That's what happens. But

36:04

the Sun basically is,

36:08

because of its big mass, it's confined

36:10

and it creates these hot dense

36:13

areas in the center of it where the fusion happens,

36:15

right? So if you have a little bit of

36:17

deuterium, tritium gas, you're not going to get, just

36:20

floating around in space, you're not going to get fusion

36:22

by itself.

36:23

I don't think something flying

36:25

off of the sun is an immediate

36:28

problem for us.

36:30

And I don't think it's a model for what we're doing

36:32

in the lab as well. As Breena said, the sun

36:34

does a,

36:35

it creates fusion, but it does it in a slightly different

36:38

way. It's confined through its own

36:40

mass because it's so heavy, it all sticks

36:42

together.

36:43

Whereas what we're doing, as I said, is,

36:46

you know, it's flying apart. It's not one, doesn't

36:48

want to stay together because it's only a little bit. Yeah.

36:50

And then if it's coming our way, right, then

36:53

the like, if it's charged particles, the magnetic

36:55

field's going to hopefully do its thing. Okay.

36:58

And, and what? Yeah. So, so, okay,

37:01

great. So not, not, not,

37:03

not, astronauts

37:03

might be a bit more worried, but. I

37:06

think they're more worried about, yeah, it's

37:08

true. Well, Mathias

37:10

and Sabrina, thank you so much for being an uninquiring

37:13

minds. It's been really incredible to

37:15

get this inside view of this really

37:17

kind of, you know, major

37:18

or 60 years in the making

37:20

discovery. Yeah. Thank

37:22

you so much. I think it's, it's a really inspiring

37:25

time and you know, it's,

37:27

we spend our careers working on this and many

37:29

people have

37:30

spent their careers working on it. And we never

37:32

got to see it because they retired. So

37:34

it's fantastic to be part of this.

37:36

Yes. Thank you very much for having us. Yeah.

37:38

Thank you for having us.

37:43

So that's it for another episode. Don't worry about

37:45

parts breaking off the sun. Thanks for listening.

37:48

and if you want to hear more, don't forget to subscribe.

37:51

If you'd like to get an ad-free version of this show, consider

37:53

supporting us at patreon.com slash

37:55

inquiring minds. I want to especially

37:58

thank David Noel, Herring Cheng, Sean

38:00

Johnson, Jordan Millar, Kyle Royhala,

38:02

Michael Galgoul, Eric Clark, Yushi

38:04

Lin, Clark Lindgren, Joelle,

38:06

Stephen Meyer, AWOL, Dale LeMaster, and Charles

38:09

Blyle. Inquiring Minds is produced

38:11

by Adam Isaac. I'm your host, Indre

38:13

Viscontis. See you next

38:15

time!