Speaker
Volodymyr Bochko
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P2.1057.pdf
Momentum-space analysis of suprathermal electrons generation under
conditions of gas puffing during runaway tokamak discharges
I.M. Pankratov1,2, V.Y. Bochko1
1
Department of Physics and Technology, V.N. Karazin Kharkiv National University
Svobody Sq.4, 61022 Kharkiv, Ukraine
2
Institute of Plasma Physics, NSC “Kharkiv Institute of Physics and Technology”
Akademicheskaya str., 1, 61108 Kharkiv, Ukraine
The energy of disruption generated runaway electrons can reach as high as tens of mega-
electron volt energy and they can cause a serious damage of plasma-facing-component
surfaces in large tokamaks like International Thermonuclear Experimental Reactor [1]. At the
same time, the quiescent runaway electron generation during the flat-top of DIII-D low
density Ohmic discharges allows accurate measurement of all key important parameters to
runaway electron excitation [2].
Using a test particle description (like [3]) that includes acceleration in the toroidal electric
field and collisions with the plasma particles the generation of suprathermal electrons is
analyzed under conditions of gas puffing. In presented modeling, the plasma parameter
behavior close to the DIII-D quiescent runaway shot #152895 parameters is used. For this
puffed discharge the growth and decay of high-frequency ECE signal was in disagreement
with the HXR and synchrotron emission signals. Possibility of formation of the suprathermal
electron population with v v|| , which is trapped in a uniform magnetic field, is shown ( v||
and v are the velocities parallel and perpendicular to the magnetic field, respectively). The
growth and decay of high-frequency ECE signal may be explained by occurrence of this
suprathermal population.
[1] Progress in the ITER physics basis: MHD stability, operational limits and disruptions.
Nuclear Fusion, 47, 128 (2007).
[2] C. Paz-Soldan, N. W. Eidietis, R. Granetz et al. Phys. Plasmas 21, 022514 (2014)
[3] V. Fuchs, R. A. Cairns., C. N. Lashmore-Davies et al. Phys. Fluids., 29, 2931 (1986)
