28 THENEWYORKER,OCTOBER11, 2021
hair; she loves scuba diving, which
made leaving California difficult. She
had attended M.I.T. as an undergrad-
uate, and at one of the early C.F.S.
meetings she found herself seated next
to her fluid-dynamics professor. “I was
thinking, I hope he doesn’t remember
what grade I got in his class,” she said.
One of Dunn’s main tasks has been
producing the magnets, including the
pancakes I saw in the West Cell Diner.
When I met her, a test of the magnets
was imminent, but Dunn told me that
she wasn’t really worried about failure.
“When they were hiring me, they stressed
that it wasn’t a physics problem but an
engineering problem,” she said. “That
appealed to me. You can’t change the
laws of physics, but an engineering prob-
lem—that can be solved.”
Dunn showed me around the C.F.S.
headquarters, a modest one-story build-
ing a fifteen-minute walk from the
M.I.T. campus. There were wooden
presses and lazy Susans and people
spooling H.T.S. wire onto metal plates
in what I can only describe as an arti-
sanal atmosphere. There was no hum
of machinery. The pancakes that were
being tested in the West Cell Diner
had evolved from being hand-fabricated
here to being made by repeatable mech-
anized processes.
Dunn said that her time at SpaceX
had accustomed her to productive fail-
ure. “We’d all watch the early rocket-
landing attempts,” she said. “One would
miss the boat entirely. The next one
would land on the boat, but then slide
off into the water. Another would land,
then tip over.” She went on, “But I re-
member having a good feeling before
the first time we landed successfully. I
made sure to go to the front row for the
viewing.” The spirit in the crowd that
day was something that still motivates
her. Dunn sees her work at SpaceX as
not very different from her work at
C.F.S.: “It’s large metallic structures
under stress.”
The day of the crucial magnet
demonstration came about six months
after I met Dunn. At around 5:30 a.m.
on September 5th, Dunn gathered with
much of her team at an outdoor tent—
on account of COVID—near the mag-
net she and her team had worked for
three years to develop. The magnet had
spent the past week being cooled down
to twenty degrees Kelvin; the air inside
it had been pumped down to a vacuum.
The plan was to run a current through
it, resulting in a magnetic field of twenty
tesla. (A kitchen magnet is about 0.001
tesla; an M.R.I. machine operates at
about 1.5 tesla; the magnets that levi-
tate high-speed trains are about five
tesla.) Under the tent, a screen displayed
a reading of the amps into the magnet,
and of the magnetic field out.
As both the current and the mag-
netic-field numbers rose, Dunn said,
“Our anxieties were about the pumps,
the valves, the vacuum system, all
that—but really it was about the un-
known unknowns.” The magnetic field
reached twenty tesla. There were hugs,
cheers, high fives, and a crowd of very
happy people. Whyte made remarks,
as did Mumgaard. Dunn and her col-
league Brandon Sorbom hosted “The
Joy and Brandon Show,” in which
they interviewed members of the team
about their contributions. “I think for
me, personally, a lot of the nervous
excitement—it was existential,” Dunn
said. “I feel we proved the science. I
feel we can make a difference. When
people ask me, ‘Why fusion? Why
not other renewables?,’ my thinking
is: This is a solution at the scale of
the problem.”S
oon after the demonstration, Paul
Dabbar, the former Under-Secretary
for Science and a visiting fellow at Co-
lumbia University’s Center on Global
Energy policy, declared in an op-ed
for The Hill that “the fusion age is
upon us.” He urged more government
support for the field. Dabbar, like many
fusion scientists, takes seriously C.F.S.’s
claims that by 2025 it will be demon-
strating a fusion device that gives out
considerably more energy than it takes
to run.
But many, many technological chal-
lenges remain before fusion will turn
on the lights in your kitchen. Will these
fusion devices sustain plasmas for suf-
ficient periods of time? Will they solve
their daunting fuel-cycle issues, and
manage their exhaust, and will the
stresses of the extreme conditions de-
stroy the devices themselves? Will there
come a time when there is jam today,
and the day after, and the day after that?
“This is difficult to judge,” Cowley,of Princeton, told me. “What C.F.S. has
done—it’s a big contribution, absolutely.”
He went on, “I’m always cautious. That’s
my personality. I do worry that this is
fitting luxury seats into a hot-air bal-
loon—and that won’t take you across
the Atlantic. I do worry that if this
doesn’t work, after all this attention, then
the whole field will have a pall over it
again for a long time.”
Cowley wavered between seeing his
perspective as sober and seeing it as too
cautious. He was the one who drew my
attention to the argument, in Edding-
ton’s fusion paper, that there is some-
thing to be said for Icarus. “My feel-
ing is that there’s still an idea that we
haven’t had yet, and that once we have
it we’ll think what fools we were not
to have had it earlier,” Cowley said.
“But the Wright brothers weren’t like
me. They weren’t scientists in a lab—
they were mechanically minded peo-
ple who had some new ideas but also
who had some luck on their side in
terms of other technologies that came
of age at the right time. C.F.S. has that
youthful spirit. C.F.S. thinks, We know
more than we think we know.” The
realm of science and invention is not
free from psychology. Cowley circled
back over his doubts, then suddenly
said, “I can’t believe there aren’t a se-
ries of steps that will get us there. I
can’t believe that we won’t be able to
do it eventually.”
In 1901, the chief engineer of the
United States Navy wrote, of heavier-
than-air flight, “A calm survey of nat-
ural phenomenon leads the engineer to
pronounce all confident prophecies for
future success as wholly unwarranted,
if not absurd.” At the time, the Wright
brothers were studying aerodynamics
in a makeshift wind tunnel; after one
particularly disheartening summer at
Kitty Hawk, Wilbur confided to Or-
ville his feeling that “not in a thousand
years will man fly.” Two years later, they
flew their plane for twelve seconds; not
too many years after that, they were fly-
ing for hours, performing figure eights
for large crowds. In response to a report
that President Theodore Roosevelt in-
tended to fly with Orville soon, Orville
said that, though he wouldn’t turn down
a request from the President, he did not
think it wise for the President to take
such chances.