BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:1
UID:UW-Physics-Event-6212
DTSTART:20201207T180000Z
DURATION:PT1H0M0S
DTSTAMP:20240319T010848Z
LAST-MODIFIED:20201203T171609Z
LOCATION: Zoom Meeting
SUMMARY:Demonstration of helium exhaust enhancement during resonant ma
gnetic perturbation (RMP) field application at DIII-D\, Plasma Physics
(Physics/ECE/NE 922) Seminar\, Edward Hinson\, UW Engineering Physics
department
DESCRIPTION: It is shown for the first time in a diverted tokamak tha
t
\nkey metrics for continuous fusion\, effective helium particle<
br>
\nconfinement time\, 𝛕_p*He\, and its ratio with energy confine
ment\,
\n𝛕_p*He/𝛕_E\, were reduced by a factor of 2-3 during
suppression of
\nedge localized modes (ELMs) by resonant magnetic
field perturbations
\n(RMPs) over the unperturbed ELMy case. Redu
ced 𝛕_p*He during RMP was
\nobserved in the core\, edge\, and p
ump plenum\, where higher helium
\npressure and concentration were
also found. Elevated ionized helium
\nline emission during ELM su
ppression\, with a decay time matching
\n𝛕_p*He\, was measured
at the inner strike point\, suggesting more
\nhelium in the unconf
ined region. These observations suggest that
\nprocesses during ap
plication of RMPs better retain helium at the edge\,
\nin excess o
f that expected from deuterium ‘pumpout\,’ where it is
\npumpe
d more quickly. A multi-reservoir model\, derived from a finite
\n
volume approximation of the continuity equation with diffusive and
\nconvective transport\, fits the helium time evolution at each of th
e
\nabove-mentioned measurements well. Transport parameters obtain
ed from
\nthese fits indicate the data are consistent with strongl
y increased
\ntransport of helium in the separatrix region during
RMP application\,
\nalthough higher core transport is also found.
These findings\, which
\nwere obtained in ITER-shaped plasmas\, pr
ovide evidence that
\napplication of RMP ELM suppression in future
devices such as ITER may
\nbe capable of matching or exceeding th
e helium impurity exhaust
\nproduced by the ELM events themselves\
, thereby helping to avoid helium
\nash buildup in a burning regim
e\, and maintain high fusion gain.
\n
\nConnection information
:
\n
\nJoin Zoom Meeting
\nhttps://uwmadison.zoom.us/j/991
56107574?pwd=RnA0ZnJHbDdlOHN1dkpFYUVYcWZpUT09
\n
\nMeeting ID:
991 5610 7574
\nPasscode: 883688
URL:https://www.physics.wisc.edu/events/?id=6212
END:VEVENT
END:VCALENDAR