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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:0
UID:UW-Physics-Event-4948
DTSTART:20181112T180500Z
DURATION:PT1H0M0S
DTSTAMP:20260419T060126Z
LAST-MODIFIED:20181030T194202Z
LOCATION:2241 chamberlin hall
SUMMARY:Advances and discoveries en route to magnetically confined el
ectron-positron plasmas\, Plasma Physics (Physics/ECE/NE 922) Seminar\
, Dr. Eve Stenson\, IPP Garching
DESCRIPTION:The large mass imbalance between ions and electrons produc
es a
\nseparation of the two species' length and time scales that
is a
\ncornerstone of traditional plasma physics. To consider th
e behavior of a
\n"pair plasma"\, comprising particles with oppos
ite charge but equal mass\,
\nis to revisit much of plasma physic
s from the ground up. Since the idea
\nwas first introduced four
decades ago\, on the order of 1000 papers have
\nexplored this to
pic via a variety of analytical and computational
\ntreatments\,
but the experimental side of the investigation is still in
\nits
nascence. Laboratory studies of matter-antimatter plasmas will
\n
enable new tests of simulation and theory predictions\, with implicati
ons
\nfor our understanding of fundamental plasma science\, astro
physical
\nphenomena in which pair plasmas play a role\, and also
traditional
\nelectron-ion plasmas.
\n
\nToward these en
ds\, the goal of the APEX (A Positron Electron eXperiment)
\ncoll
aboration is to create and study electron-positron plasmas confined
\nin the magnetic field of a levitated dipole. A key milestone tha
t was
\nrecently achieved is the demonstration of lossless inject
ion of
\nlow-energy (e.g.\, 5-eV) positrons into a prototype dipo
le trap\, in which
\nthe positrons can then be confined for sever
al seconds (corresponding to
\nhundreds of thousands of toroidal
transits). Another recent result of
\nnote is the discovery that
phosphor screens (long used to diagnose both
\nmatter and antima
tter) produce significantly more luminescence from
\nincident pos
itrons than incident electrons. This has potential to be a
\nnew
means of investigating luminescent materials\, in addition being of <
br>
\nsignificant utility for nonperturbatively diagnosing low-energy
positron
\nbeams and plasmas.
\n
\nSUPPORTED IN PART BY A
GENEROUS GRANT FROM THE WOMEN'S SCIENCE &
\nENGINEERING LEADERSH
IP INSTITUTE (WISELI)
URL:https://www.physics.wisc.edu/events/?id=4948
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