THENEWYORKER,OCTOBER11, 2021 27
ous. Couldn’t some of it leak out of the
magnetic bottle, with catastrophic con-
sequences? As an answer, Mumgaard
twisted a valve to let a tiny bit of air into
the glass tube; the plasma vanished. “Peo-
ple think of fusion like they think of fis-
sion, as this overwhelming reaction, but,
really, it’s such a delicate process,” Whyte
said. “It’s like a candle in the wind. Any-
thing can blow it out. Even a single
human breath.”
M
uch of what Mumgaard and
Whyte showed me at P.S.F.C. was
the standard part of fusion science. A
magnetic bottle is an old idea, and plasma
is the most common state of matter; it’s
the state that 99.9 per cent of the uni-
verse is in. Scientists have been studying
plasmas, and magnetic bottles, for de-
cades. Much of what seems difficult about
fusion to a plasma physicist—How will
tritium be produced and recycled? How
can edge-localized modes be anticipated
and countered? Will quantum comput-
ing enable the study of electromagnetic
waves in a plasma?—is so much Greek
to a layperson. In contrast, much of what
seems difficult about fusion to a layper-
son—super-hot plasmas, magnetic bot-
tles, toroidal coils—is bread and butter
for a fusion scientist.
“As energy, fusion is in some sense
very prosaic,” Whyte said. “It’s an intense
source of heat.”
“And we’ve been turning heat into
electricity since James Watt,” Mumgaard
added, referring to the eighteenth-century
Englishman whose development of
the steam engine enabled the Industrial
Revolution. Mumgaard often stresses
that C.F.S. is building a “standard, even
boring” machine, using “boring, non-
innovative” technology, “but for very
non-boring reasons.”
The one exception is the H.T.S. mag-
net—the most exciting element of the
research, and the one that raises the most
doubt within the scientific community.
“I just wonder about the material stresses
of such a powerful magnetic field,” one
scientist said to me. “H.T.S. magnets will
definitely be used in future tokamaks, no
doubt, but I suspect they’ll be used with
a weaker magnetic field.”
“Most of the criticism we hear is not
about the science but about the timeline,”
Mumgaard said. The magnets inside ITER
took thirty years to develop. “It took us
three years.” He could barely repress a
grin; it was the one moment of boyish
bullishness and ego that I saw in him.
SPARC will have eighteen H.T.S. mag-
nets; each will be composed of sixteen
“pancakes”—eight-foot-tall stackable
D-shaped slices. I met a pancake in the
West Cell, an enormous open laboratory
space at M.I.T. which resembles an air-
plane hangar. What with all the pan-
cakes and doughnuts being tested there,
the West Cell has come to be called the
West Cell Diner. The pancakes were
given names in alphabetical order. The
first production pancake was named Egg.
When I was there, I saw Strawberry. “We
originally planned to have a pancake
breakfast for the team when we finished,”
Whyte said. “COVID is making that look
less likely.”
Strawberry was, incidentally, beauti-
ful. It comprised coils of steel, copper,
H.T.S., and helium coolant, because even
a high-temperature superconductor has
to be kept very cold. (In its internal struc-
ture, the magnet was more croissant than
pancake.) “I remember when the first pan-
cake was done, and we were moving it so
delicately,” Whyte said. “Our hearts were
in our mouths—it was, like, Holy cow.
Then, the other week, it was the fifteenth
pancake. We rolled it over, connected it,
like we’d done it a thousand times.”
C.F.S. is not the only enterprise try-
ing to be the Wright brothers. In 2001,
Michel Laberge left his job as a physi-
cist and engineer at a printing company
and began work on a fusion project that
evolved into General Fusion, a Canada-
based company developing a technology
called magnetized target fusion. General
Fusion has the backing of Jeff Bezos,
though some plasma physicists note that
they haven’t seen enough published work
to know how the fusion device is pro-
gressing. The U.K. Energy Agency has
commissioned General Fusion to build
a demonstration plant in Culham, Ox-
fordshire, where major fusion records
were set in the nineteen-nineties. Gen-
eral Fusion has announced its intention
to open the plant in 2025, the year that
C.F.S. plans to turn on its switch at a
SPARC demonstration plant being built
in Devens, Massachusetts. There are at
least twenty fusion startups now, all ben-
efitting from technological advances in
3-D printing and artificial intelligence.
The companies have different risks. TAE,
in Orange County, California, uses a fuel,
boron, that requires higher temperatures
but generates no radioactive by-prod-
ucts. Physicists describe boron fusion as
“elegant” and even “perfect,” if also, in
certain ways, more difficult. Michl Bin-
derbauer, the head of TAE, told me, “I
don’t call these other companies my com-
petitors, I call them my compatriots. We
have the same goals, and it will be won-
derful for any of us to get there.”
C
.F.S.’s seventh hire was Joy Dunn,
an aerospace engineer recruited
from SpaceX and made head of man-
ufacturing. Dunn, who is thirty-fi ve,
has a youthful face and short, rockabilly
“Would you like to sing the national anthem before dinner?”
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