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SUMMARY:Driving intrinsic rotation in tokamaks using up-down asymmetric pl
 asma shaping
DTSTART:20160415T103000
DTEND:20160415T113000
DTSTAMP:20260920T013708Z
UID:720219a2811f97ff46beb605cdc316d70668438cc4e251262af65612
CATEGORIES:Conferences - Seminars
DESCRIPTION:Justin Ball\, Oxford University & Culham Center for Fusion Ene
 rgy\, UK\nRecent work demonstrated that breaking the up-down symmetry of t
 okamaks removes a constraint limiting intrinsic momentum transport\, and h
 ence toroidal rotation\, to be small [Parra\, et al. Phys. Plasmas (2011)]
 . We show through MHD analysis that low order flux surface shaping (e.g. e
 longation\, triangularity) is optimal for introducing up-down asymmetry th
 roughout the plasma. We then demonstrate a particular tilting symmetry of 
 the flux surface shape in the local nonlinear df gyrokinetic model. This s
 ymmetry establishes an important distinction between the momentum transpor
 t in tokamaks with mirror symmetric flux surfaces and tokamaks with flux s
 urfaces that lack mirror symmetry. Using GS2\, a local df gyrokinetic code
  that self-consistently calculates momentum transport\, we first numerical
 ly verify this gyrokinetic symmetry. Then we show the momentum flux calcul
 ated by GS2 is consistent with both TCV experimental measurements [Camenen
 \, et al. Phys. Rev. Lett. (2010)] and analytically derived scalings in th
 e limit of high order  flux surface shaping. Lastly\, we investigate the 
 influence of the Shafranov shift on momentum transport. The results of thi
 s work suggest that up-down asymmetry can generate sufficient rotation to 
 stabilize the resistive wall mode in reactor-sized devices.
LOCATION:PPB 019
STATUS:CONFIRMED
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