Effect of magnetic and electrostatic fluctuations on the runaway electron dynamics in tokamak plasmas
- Universidad Carlos III de Madrid, Avenida de la Universidad 30, Leganes, 28911-Madrid (Spain)
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8070 (United States)
- Associazione Euratom-ENEA CRE, 00044-Frascati (Italy)
A test particle description of the runaway dynamics [J.R. Mart{acute i}n-Sol{acute i}s {ital et al.}, Phys. Plasmas {bold 5}, 2370 (1998)] is extended to investigate the behavior of runaway electrons in the presence of fluctuations of electric and magnetic fields. The interaction with the fluctuations is accounted for via a friction force with an effective {open_quotes}collision{close_quotes} frequency determined by the fluctuation induced radial diffusion coefficient. It is shown that both the runaway generation process and the maximum runaway energy can be noticeably affected by magnetic fluctuations. The test particle model is then used to discuss a proposed runaway control scheme via induced magnetic turbulence, with particular emphasis to situations like major disruptions, where a large number of runaway electrons and high runaway energies are expected. It is found that the efficiency of such scheme can in some cases be jeopardized by drift orbit effects as well as by the coexistence of stochastic magnetic regions with good magnetic surfaces. {copyright} {ital 1999 American Institute of Physics.}
- OSTI ID:
- 686540
- Journal Information:
- Physics of Plasmas, Vol. 6, Issue 10; Other Information: PBD: Oct 1999
- Country of Publication:
- United States
- Language:
- English
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