26 THENEWYORKER,OCTOBER11, 2021
philanthropy—one way or another, they
would make their good-enough fusion
power plant real.
O
n September 30, 2016, M.I.T.’s old
experimental fusion device, which
had been running for twenty-five years,
was obliged to shut down by midnight.
“This device graduated more than a hun-
dred and fifty Ph.D.s,” Whyte said wist-
fully. “It set records, even though it’s a
hundred times smaller than ITER.” Al-
though M.I.T. was never told why the
device was shut down—the Department
of Energy continued to fund two other
tokamak projects in the U.S.—there was
speculation that the reason was that it
was the smallest. “Which is ironic, be-
cause smaller is where we’re trying to go,”
Whyte said. The researchers ran exper-
iments on the machine until the last per-
mitted minute. At 10:30 P.M., they set a
world record for temperature and pressure.
At midnight, they shared champagne.
“I went home a little after midnight,
but I couldn’t sleep,” Whyte said. In his
home office, with his wife’s paintings of
trees and flowers on the wall, he started
going over the data from the final exper-
iments: “I was just sort of plugging in
what our results would mean in a ma-
chine with a higher magnetic field,” as
would be produced with H.T.S. magnets.
“It meant spARC could provide a hun-
dred million watts.” This was even more
than the team had speculated in Austin.
Whyte was seeing fusion’s holy grail.
The M.I.T. team continued to dedi-
cate its time to ARC/SPARC, quilting to-
gether fellowships and grants. At one
point, to make payroll, technicians went
into the basement and loaded trucks with
scrap copper to sell. SPARC Underground
was set up—a group of interested scien-
tists who met regularly, to discuss plans
and work through difficulties. They
needed to buy as much H.T.S. as they
could, in order to learn more about the
material’s characteristics—hammer it,
heat it, freeze it, send current through it.
“I remember so well the first shipment
of H.T.S.,” Mumgaard said. “We waited
for months to get this reel of material.
It was only five hundred metres. Now, if
we’re not talking ten kilometres, we’re
not talking anything. These days, you
can order this stuff on Alibaba.com.
But then—it was such a moment.”
The team had to solve engineering
problems—it also had to solve business
problems, including convincing suppli-
ers that there was a market for the ma-
terial, so that more would be made. “We
met with them and asked them if they
had considered fusion as a market,” Mum-
gaard told me. “They were, like, ‘No way,
that’s not a real thing.’” After two years
of extensive lab work and dreamy conver-
sations over five-dollar pitchers of Miller
High Life at the Muddy Charles Pub,
SPARC Underground became Common-
wealth Fusion Systems, a seven-person
private fusion-energy company with an
ongoing relationship with M.I.T. (C.F.S.
funds research at M.I.T., which shares
its intellectual resources and some lab
space with C.F.S.; patents are filed jointly.)
Some of C.F.S.’s funders are European
energy companies, and some are philan-
thropists. By 2021, the company employed
about three hundred people, many of
them veterans of SpaceX and Tesla.
“Energy is a market,” Mumgaard said.
“If you knew there was a ten-trillion-dol-
lar market out there—that is a pull. You
couldn’t even have said there was a mar-
ket that big for computers, or for social
media. But you can say that about energy.”
T
he Plasma Science and Fusion Cen-
ter, at the northwest corner of the
M.I.T. campus, is only a few minutes’
walk from the Cambridge campuses of
Pfizer and Moderna. In March, Whyte
and Mumgaard met me at the front steps.
Mumgaard is now the C.E.O. of C.F.S.;
Whyte, a co-founder, remains at M.I.T.
They wore T-shirts and had pandemic-
untrimmed wavy hair, giving them the
look of ambitious surfers. I was there to
meet them, but also to meet their mag-
net, which was still under construction.
Maybe it would work, or maybe it would
send the team back to the planning stages
for years. It was a warm and sunny day.
If Kool-Aid had been on offer, I would
have drunk not one glass but two.
Aristotle described magnetism as the
workings of the soul inside a stone. Mag-
nets have been used to navigate ships, to
levitate high-speed trains, to image the
inside of a human body, and to move
iron filings to make a silly beard on a
plastic-bubble-encased drawing of a face.
In 1951, the physicist Lyman Spitzer sug-
gested that a magnetic field could serve
as a bottle in which to contain a plasma
that re-created the pressure and the tem-
perature inside a star. Magnets have been
a centerpiece of fusion research ever since.
Mumgaard and Whyte gave me a
tour of their lab spaces. The first stop
was at what looked like a lectern, in a
cubicled room. The room’s distant wall
was the control board for M.I.T.’s first
experimental fusion device, from the
nineteen-seventies. The lectern featured
pictures of common plasmas: the sun,
lightning, the northern lights, magnetic
fusion, and a neon sign reading “OPEN.”
Mounted on the lectern was a hollow
glass tube with copper wire coiled around
it in two places. The wire was set up so
that a current could be run through it,
and the glass tube was suspended over a
metal plate. You may remember a demon-
stration, from your high-school science
class, of an electric current being run
through coiled wires, generating an elec-
tromagnetic field—this was basically a
fancier version of that. “You can turn it
on,” Mumgaard said.
I pushed a black button. A purring
noise began. “That’s the sound of the
vacuum draining the air from the glass
tube,” Mumgaard said. He turned a valve,
releasing a tiny bit of hydrogen gas into
the tube. A hot-pink glowing light ap-
peared, nested within the glass tube like
a matryoshka doll. The magnetic field
that contained the pink plasma was vis-
ible in the form of empty space between
the glass and the glow. “That pink is the
superheated plasma,” Mumgaard said.
“It’s at least a thousand degrees. But touch
the glass.” The glass was cool. “Now touch
the copper wires.” They were warm, but
not hot. The warmth of the copper wires
was not on account of their proximity to
the superheated plasma but, rather, be-
cause copper is not a perfect conductor;
some of the energy running through it
is lost in the form of heat. Superconduc-
tors lose almost no heat—which is energy.
It seemed impossible that the pink
plasma inside the tube, which was as hot
as lightning, wasn’t in some way danger-
