%0 Journal Article
%A Abdullaev, S. S.
%A Finken, K. H.
%A Wongrach, K.
%A Tokar, M.
%A Koslowski, H. R.
%A Willi, O.
%A Zeng, L.
%T Mechanism of runaway electron beam formation during plasma disruptions in tokamaks
%J Physics of plasmas
%V 22
%N 4
%@ 1089-7674
%C [S.l.]
%I American Institute of Physics
%M FZJ-2015-03026
%P 040704 
%D 2015
%X A new physical mechanism of formation of runaway electron beams during plasma disruptions in tokamaks is proposed. The plasma disruption is caused by a strong stochastic magnetic field formed due to nonlinearly excited low-mode number magnetohydrodynamic (MHD) modes. It is conjectured that the runaway electron beam is formed in the central plasma region confined inside the intact magnetic surface located between q = 1 and the closest low–order rational magnetic surfaces [q = 5/4 or q = 4/3,…]. It results in that runaway electron beam current has a helical nature with a predominant m/n = 1/1 component. The thermal quench and current quench times are estimated using the collisional models for electron diffusion and ambipolar particle transport in a stochastic magnetic field, respectively. Possible mechanisms for the decay of the runaway electron current owing to an outward drift electron orbits and resonance interaction of high–energy electrons with the m/n = 1/1 MHD mode are discussed.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000353837200005
%R 10.1063/1.4919253
%U https://juser.fz-juelich.de/record/190067