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VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
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SEQUENCE:1
UID:UW-Physics-Event-9409
DTSTART:20250929T170000Z
DTEND:20250929T180000Z
DTSTAMP:20260413T083911Z
LAST-MODIFIED:20250919T155006Z
LOCATION:2241 Chamberlin Hall
SUMMARY:Centrifugal confinement in mirrors and axisymmetric scrape-off
  layers\, Plasma Physics (Physics/ECE/NE 922) Seminar\, Timothy Stoltz
 fus-Dueck\, PPPL
DESCRIPTION:In the centrifugal-mirror confinement concept\, parallel c
 onfinement by the mirror force is supplemented with a parallel centrif
 ugal force driven by supersonic ExB rotation in the azimuthal/toroidal
  direction.  Although this approach practically closes the loss cone a
 nd naturally exhibits stabilizing ExB shear\, it requires a very large
  radial voltage difference\, presenting engineering challenges for the
  insulating end plates. In principle\, the addition of a strong azimut
 hal field could reduce the required voltage\, since the simple azimuth
 al ExB drift would be replaced by more rapid azimuthal trapped-particl
 e precession. Also\, if the mirror ratio is large enough\, newly-ioniz
 ed ions are accelerated to the necessary parallel velocities in their 
 first bounce orbit\, both confining and significantly heating them. Un
 fortunately\, MHD analysis shows that the centrifugal-force-confining 
 plasma current is purely azimuthal. This implies that only the axial m
 agnetic field contributes to the confining magnetic pressure\, severel
 y limiting the usefulness of the azimuthal magnetic field in a beta-li
 mited plasma scenario.  However\, the single-particle confinement prop
 erties may prove useful in non-beta-limited scenarios.  For example\, 
 centrifugal confinement could slow parallel losses from an axisymmetri
 c scrape-off-layer\, particularly in an ST with a deeply inboard X-poi
 nt.  In addition to supporting large density and temperature drops fro
 m midplane to target\, such confinement could substantially broaden th
 e heat-flux deposition width\, while the SOL rotation directly stabili
 zes resistive wall modes.
URL:https://www.physics.wisc.edu/events/?id=9409
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