Ref: http://focus.aps.org/story/v12/st18
Phys. Rev. Lett. 91, 205004 (issue of 14 November 2003)
Electrons in a plasma are like sheep in a field--they gambol around
and sometimes need a good prod to nudge them in the right direction.
In the 14 November PRL, a team describes a seemingly magical method
for providing that prod efficiently for electrons orbiting around a
fusion reactor. They propose using electric and magnetic fields to
create a one-way wall that lets electrons through in one direction
but blocks them in the other. The technique could also lead to a new
way of trapping charged particles. The concept is reminiscent of
"Maxwell's Demon," a character dreamed up by a physicist studying
thermodynamics in the 19th century.
In a doughnut-shaped fusion reactor called a tokamak, researchers use
magnetic fields to keep the superhot plasma from splattering against
the walls and prematurely halting the reactor. They produce part of
this containment field by driving some of the plasma's electrons
around the ring in one direction. But the usual methods for
generating this current require pumping large amounts of radio wave
energy into the plasma, much of which is wasted heating some
electrons more than necessary.
See: http://focus.aps.org/story/v12/st18
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