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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:1
UID:UW-Physics-Event-8985
DTSTART:20241118T180500Z
DTEND:20241118T190000Z
DTSTAMP:20260413T184745Z
LAST-MODIFIED:20241106T192703Z
LOCATION:1610 Engineering Hall
SUMMARY:Drift-cyclotron loss cone instability in 3D kinetic-ion simula
 tions of WHAM\, Plasma Physics (Physics/ECE/NE 922) Seminar\, Aaron Tr
 an\, University of Wisconsin-Madison
DESCRIPTION:WHAM's "peak-performance" beam-ion plasma may induce drift
 -cyclotron loss-cone (DCLC) instability: a coupled ion Bernstein / dri
 ft wave excited by the plasma’s radial density gradient and loss-con
 e velocity distribution. We present 3D plasma simulations\, using kine
 tic ions and isothermal fluid electrons\, of various WHAM configuratio
 ns with sloshing (45 deg. pitch angle) beam-ion distributions from the
  collisional Fokker-Planck code CQL3D-m as an initial condition. Edge-
 localized electrostatic waves grow and saturate in ~1–10 μs with ω
  ~ 1–2× the ion cyclotron frequency. Wave properties can be explain
 ed by linear theory of DCLC in a planar slab. DCLC scattering fills th
 e loss cone\, so particle confinement is set by axial free streaming (
 aka "gas dynamic" confinement). Adding cool (~1 keV) ions to the plasm
 a edge improves confinement by ~2–5×. I will also briefly comment o
 n (i) other ways to stabilize DCLC\, (ii) how DCLC fits into a broader
  landscape of instabilities in mirrors\, and (iii) the effect of exter
 nally-driven shear flows.
URL:https://www.physics.wisc.edu/events/?id=8985
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