Abstract Details
Abstracts
Author: Diego del-Castillo-Negrete
Requested Type: Poster
Submitted: 2017-03-17 08:17:21
Co-authors: L. Carbajal, D. Spong, S. Seal, and L. Baylor
Contact Info:
ORNL
Oak Ridge National Laboratory
Oak Ridge, Tennessee 37831
USA
Abstract Text:
The dynamics of runaway electrons (RE) in fusion plasmas span a wide range of time scales, from the fast gyro-motion,∼1 ps, to the observational time scales,∼10 ms→1 s. To cope with this scale separation, RE are usually studied within the bounce-average or the guiding center approximations. Although these approximations have yielded valuable insights, a study with predictive capabilities of RE in fusion plasmas calls for the incorporation of full orbit effects in configuration space in the presence of 3-D magnetic fields. We present numerical results on this problem using the Kinetic Orbit Runaway electrons Code (KORC) that follows relativistic electrons in general electric and magnetic fields under the full Lorentz force, collisions, and radiation losses. Radiation damping is included using the Landau-Lifshitz formulation of the Abraham-Lorentz-Dirac force. The main focus is on full orbit orbits effects on synchrotron radiation. We shown that even in the absence of magnetic field stochasticty, neglecting orbit dynamics introduces significant errors in the computation of the total radiated power and the synchrotron spectra. The statistics of collisionless (i.e. full orbit induced) pitch angle dispersion, and its key role played on synchrotron radiation, are studied in detail. Results on the pitch angle dependence of the spatial confinement of RE, and on full orbit effects on the competition of electric field acceleration and radiation damping are also presented. Finally, we explore the limitations of gyro-averaging in the relativistic regime. DIII-D and ITER-like parameters are used in the simulations.
Research sponsored by the LDRD Program of ORNL, managed by UT-Battelle, LLC, for the U.S. DoE under Contract No. DE-AC05-00OR22725.
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