BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:2
UID:UW-Physics-Event-8285
DTSTART:20230607T150000Z
DTEND:20230607T170000Z
DTSTAMP:20260414T033146Z
LAST-MODIFIED:20230606T145328Z
LOCATION:B343 Sterling or https://uwmadison.zoom.us/j/93620614293?pwd=
 TC9WMTE1dSs3OGQ4ZmQyY09KcEJ4UT09
SUMMARY:Lundquist Number Scaling in the MST Reversed-Field Pinch\, Gra
 duate Program Event\, Steph Kubala\, Department of Physics Graduate St
 udent
DESCRIPTION:Nonlinear MHD fluctuations appear in both natural and magn
 etic confinement settings\, such as the solar wind\, self-organization
  dynamics in the RFP and spheromak\, and current disruptions in tokama
 k plasmas. In this thesis\, parameter scaling experiments oriented tow
 ard nonlinear MHD dynamics in RFP plasmas are presented. Experimental 
 data have been gathered spanning a wide range of parameter space chara
 cterized by Lundquist number\, S ∼ 104 −107\, and density  where i
 s the empirical density limit. A new programmable power supply allows 
 low-current\, low-S operation\, which overlaps with parameters availab
 le in numerical modeling. Experimental S scalings of magnetic fluctuat
 ion amplitude agree well with those from the nonlinear MHD codes DEBS 
 and NIMROD. A transition from quasi-continuous activity to bursty rela
 xation having discrete sawtooth events is observed in going from low t
 o high S\, with a threshold at around S ∼ 105. The spectral properti
 es of the magnetic fluctuations change at this transition\, including 
 a reduction in fluctuation phase velocity that suggests plasma flow an
 d/or flow profile changes. Momentum transport and flattening of the fl
 ow profile are known features associated with sawtooth relaxation in R
 FP plasmas.
URL:https://www.physics.wisc.edu/events/?id=8285
END:VEVENT
END:VCALENDAR