Speaker
Dr
Jay Anderson
(University of Wisconsin)
Description
The existence of a magnetic-island induced gap in the shear Alfvén continuum was predicted numerically [Biancalani et al. PRL 2010], but only recently have experimental observations of the MIAE been made in stellarator[Sun et al. PPCF 2015] and RFP plasmas [Cook et al. submitted PPCF 2016]. As the role of 3D magnetic fields in tokamaks grows in prominence, associated changes in the Alfvénic spectral properties, including MIAEs, are anticipated. The core of the NBI-heated RFP plasma exhibits several unique variants of axisymmetry-breaking magnetic perturbations that impact fast ion confinement and stability.
The appearance of magnetic islands and associated magnetic stochasticity is controllable. A well-formed core-localized island is adjustable in size, ideal for study of the MIAE. While the RFP is nominally axisymmetric, in the quasi-single-helicity limit the dominant island envelops the magnetic axis, producing a stellarator-like three dimensional geometry. Here we present observations of fast ion transport in the presence of MIAEs in a RFP plasma. We further show a relative insensitivity of fast ion confinement to magnetic stochasticity, but a strong response to a coherent, 3D core perturbation.
| Country or International Organization | U.S. A. |
|---|---|
| Paper Number | EX/P5-16 |
Primary author
Dr
Jay Anderson
(University of Wisconsin)
Co-authors
A. Ivanov
(Budker Institute of Nuclear Physics)
C. Cook
(University of Wisconsin-Madison)
C. Hegna
(University of Wisconsin-Madison)
Dr
Donald Spong
(Oak Ridge National Laboratory)
J. Boguski
(University of Wisconsin-Madison)
J. Kim
(University of Wisconsin-Madison)
Prof.
John Sarff
(University of Wisconsin-Madison)
K. McCollam
(University of Wisconsin-Madison)
P. Bonofiglo
(University of Wisconsin-Madison)
S. Hirshman
(Oak Ridge National Laboratory)
S. Polosatkin
(Budker Institute of Nuclear Physics)
S. Sears
(University of Wisconsin-Madison)
V. Belykh
(Bunker Institute of Nuclear Physics)
V. Davydenko
(Budker Institute of Nuclear Physics)
W. Capecchi
(University of Wisconsin-Madison)
