Electron cyclotron current drive under different operational regimes in tokamak plasma

Abstract

With a given density profile of plasma,the temperature profiles of the plasma operating in the negative central magnetic shear mode,the H-mode and L-mode of conventional magnetic shear,are calculated respectively by applying the energy equation of electrons and ions,according to the thermal conductivity in different operational regimes.And then the electron cyclotron current drive and wave power deposition in the above modes are investigated with the relativistic Fokker-Planck equation incorporated into a ray tracing code.The result shows that in the mode of negative central magnetic shear,the current drive efficiency is the highest,meanwhile the zones of power deposition and current profile are wide.In the H-mode of conventional magnetic shear,the current drive efficiency is low,and the zones of power deposition and current profile are narrow.In the L-mode of conventional magnetic shear,the current drive efficiency is the lowest,the zones of power deposition and current profile are very narrow.

Numerical simulation of electron cyclotron current drive characteristics on EAST

“…[3] ECCD is one of the main means of controlling MHD activity in ITER. [4] Stabilization of MHD by ECCD has been observed in HL-2A, [5,6] DIII-D, [7] JT-60U, [8] etc.…”

Numerical analysis of the optimized performance of the electron cyclotron wave system in a HL-2M tokamak

“…Electron-cyclotron current drive (ECCD) has become a widely used way to drive current and stabilize magnetohydrodynamic (MHD) instabilities in toroidal magnetic confinement devices, since the electron-cyclotron (EC)-driven current profiles are spatially localized and the EC current drive efficiency is competitive with other approaches, such as neutral beam. [1][2][3][4] The HL-2M project is the up-grade of the HL-2A tokamak with plasma elongation up to 1.8. The goal of the HL-2M is to illuminate important research issues such as the physics of plasma confinement, transport, high energy particles, MHD stability, and the interaction between the first wall and plasma for fusion study.…”

Avalanche Phenomenon of Superthermal Electrons Measured by SDD with New SPHA during ECRH

“…[1] The plane mirrors of ECRH antenna can be rotated in the toroidal and poloidal directions, [2] thereby it can provide on/off-axis heating, and ECCD experiment. [3] Time evolution of soft x-ray spectra is measured by SDD system, the thermal and superthermal electron temperatures are derived according to energy spectra. Because of the ratio of peak counts to background counts is very high in the measurements of energy spectra for the mono-energy x-ray reference sources such as M nkα (5.894 keV), M okα,kβ (17.44, 19.63 keV), p/b ≥ 400-3000, these spectra also can be regarded as the electron velocity distributions roughly.…”