Speaker
Description
See full abstract here:
http://ocs.ciemat.es/EPS2019ABS/pdf/P2.1103.pdf
The Hall effect, defined as the separation of electric charges of opposite sign when they move in a magnetic field, is suggested to contribute substantially to the observed negative radial electric field E_r in the core plasma in tokamaks and, respectively, to the spontaneous/intrinsic rotation of plasma. A detailed study of the Hall effect in plasmas began with the study in [1] -- within the framework of two-fluid magnetohydrodynamics (2FMHD) -- of the effect of the frozenness of magnetic field mainly in the electron component of plasma. This effect is important for stationary plasma flows [2], and it plays a dominant role in plasma open switches, Z-pinches, plasma foci, and is widely studied in the literature [3]. In the 2F-MHD, the tokamak poloidal magnetic field compresses only the plasma electrons (the pinch by toroidal electric current), and this separation of electric charges produces E_r which, in turn, generates "spontaneous" plasma rotation in the crossed ExB fields. A simple way to evaluate the Hall effect contribution to the E_r value, using the independently measured space distributions of magnetic field, electron pressure and plasma rotation velocity, is suggested. Application of this procedure to experimental data from the TM-4 [4] and T-10 [5] tokamaks yields high negative values of Er in the core plasma (~ few hundreds of V/cm) which are in qualitative agreement with the measured values (~ 100 V/cm). The data from other tokamaks are considered as well. The results suggest that the contribution of other mechanisms (e.g., neoclassical kinetics) to E_r (and spontaneous/intrinsic plasma rotation) in tokamaks should be treated with account of a strong hydrodynamic effect of the Ampère force, described in the framework of the 2F-MHD.
References
[1]. A.I. Morozov and A.P. Shubin 1964 Sov. Phys. JETP 19, 484.
[2]. A.I. Morozov and L.S. Solov'ev, in Reviews of Plasma Physics, Ed. by M.A. Leontovich (Atomizdat,
Moscow, 1974; Consultants Bureau, New York, 1980), Vol. 8. [3]. A.S. Kingsep, K.V. Chukbar, and V.V. Yan'kov, in Reviews of Plasma Physics, Ed. by B.B.
Kadomtsev (…nergoizdat, Moscow, 1987; Consultants Bureau, New York, 1990), Vol. 16.
[4]. V.I. Bugarya, et al. 1985 Nucl. Fusion 25 1707.
[5]. A.V. Melnikov, et al. 2013 Nucl. Fusion 53 093019.
