| Title | Investigation of fast particle driven instabilities by 2D electron cyclotron emission imaging on ASDEX Upgrade |
| Publication Type | Journal Article |
| Year of Publication | 2011 |
| Authors | I.G.J. Classen, P. Lauber, D. Curran, J.E Boom, B.J Tobias, C.W. Domier, NC Luhmann, Jr., H.K Park, M.G Munoz, B. Geiger, M. Maraschek, M.A VanZeeland, S. da Graca |
| Journal | Plasma Physics and Controlled Fusion |
| Volume | 53 |
| Issue | 12 |
| Pagination | 124018 |
| Date Published | Dec |
| Type of Article | Article |
| ISBN Number | 0741-3335 |
| Keywords | ALFVEN MODES, CASCADES, EIGENMODES, STABILITY, TOKAMAK |
| Abstract | Detailed measurements of the 2D mode structure of Alfven instabilities in the current ramp-up phase of neutral beam heated discharges were performed on ASDEX Upgrade, using the electron cyclotron emission imaging (ECEI) diagnostic. This paper focuses on the observation of reversed shear Alfven-eigenmodes (RSAEs) and bursting modes that, with the use of the information from ECEI, have been identified as beta-induced Alfven eigenmodes (BAEs). Both RSAEs with first and second radial harmonic mode structures were observed. Calculations with the linear gyro-kinetic code LIGKA revealed that the ratio of the damping rates and the frequency difference between the first and second harmonic modes strongly depended on the shape of the q-profile. The bursting character of the BAE type modes, which were radially localized to rational q surfaces, was observed to sensitively depend on the plasma parameters, ranging from strongly bursting to almost steady state. |
| DOI | 10.1088/0741-3335/53/12/124018 |
| Division | FP |
| Department | PDG |
| PID | 32afd99893443c77ea31d2a8a80d4e3d |
| Alternate Title | Plasma Phys. Control. Fusion |
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