BEGIN:VCALENDAR
VERSION:2.0
PRODID:icalendar-ruby
CALSCALE:GREGORIAN
X-WR-CALNAME:PSFC Seminar: D. Battaglia
X-WR-TIMEZONE:Eastern Time (US & Canada)
BEGIN:VEVENT
DTSTAMP:20260617T072031Z
UID:tag:localist.com\,2008:EventInstance_37889228742180
DTSTART:20210930T190000Z
DTEND:20210930T200000Z
DESCRIPTION:EP H-mode on NSTX\n\nDevon Battaglia\, Princeton Plasma Physics
  Laboratory\n\nSpherical tokamaks\, such as the National Spherical Torus E
 xperiment (NSTX)\, leverage low aspect ratio to achieve large bootstrap cu
 rrent fraction (fBS ≥ 0.5) at large Greenwald density fraction (fGW > 0.
 7) with potentially beneficial stability and confinement properties for fu
 ture steady-state reactor concepts.  For example\, the critical pressure g
 radient for kinetic ballooning mode (KBM) instabilities is reduced at low 
 aspect ratio leading to H-mode pedestals that can be wider compared to con
 ventional aspect ratio tokamaks.  It was observed on NSTX that at sufficie
 ntly low collisionality the entire pressure profile is limited by the KBM 
 below the resistive kink-peeling stability limit leading to a robustly ELM
 -free regime. At the lowest collisionalities\, the discharges transitioned
  to the ELM-free Enhanced Pedestal (EP) H-mode regime with a significant i
 ncrease in the edge ion temperature and rotation gradients\, a beneficial 
 decrease in the impurity accumulation relative to standard ELM-free regime
 s and the achievement of the largest normalized energy confinement on NSTX
  (H98y\,2 > 1.3). EP H-mode is the result of a positive feedback interacti
 on between the neoclassical ion energy transport and instability-driven (s
 uch as KBM) particle transport.  The unique ELM-free regimes at low aspect
  ratio expand the physics basis needed to optimize steady-state reactor de
 signs that require simultaneous achievement of high energy confinement and
  bootstrap current without ELMs.
LOCATION:
SUMMARY:PSFC Seminar: D. Battaglia
URL;VALUE=URI:https://calendar.mit.edu/event/psfc_seminar_d_battaglia
CATEGORIES:Conferences/Seminars/Lectures
END:VEVENT
END:VCALENDAR