In a tokamak plasma, shear Alfvén waves （SAWs） are generally characterized by a continuous spectrum with gaps, due topoloidal symmetry breaking. For low frequencies, ｜ω｜〈〈｜ωA｜=νA/qR, it has been shown ...In a tokamak plasma, shear Alfvén waves （SAWs） are generally characterized by a continuous spectrum with gaps, due topoloidal symmetry breaking. For low frequencies, ｜ω｜〈〈｜ωA｜=νA/qR, it has been shown that the SAW continuum can becomeunstable due to finite ion temperature gradient. Here, νA is the Alfvén speed, q and R are the safety factor and the major radius of the flux surface, respectively. Recently, it has been shown, with the multiple scale asymptotic technique, that discrete modes may exist in an unstable shear Alfvén continuous spectrum, due to finite ion Larmor radius （FLR） and finite drift-orbit width （FOW） effects in tokamak plasmas which are stable with respect to ideal magnetohydrodynamic （MHD） instabilities .展开更多
In this paper, the electron temperature gradient （ETG） instability and corresponding turbulent transport in toroidal plasmas with negative magnetic shear is studied using the integral eigenvalue equations. The full ...In this paper, the electron temperature gradient （ETG） instability and corresponding turbulent transport in toroidal plasmas with negative magnetic shear is studied using the integral eigenvalue equations. The full electron kinetics is considered and the behaviours of the modes and the transport in the parameter regimes close to the instability threshold are emphasized. The fitting formulas of the critical gradient, for negative magnetic shear, are given.展开更多
基金Supported by the National Natural Science Foundation of China（10135020）
文摘In a tokamak plasma, shear Alfvén waves （SAWs） are generally characterized by a continuous spectrum with gaps, due topoloidal symmetry breaking. For low frequencies, ｜ω｜〈〈｜ωA｜=νA/qR, it has been shown that the SAW continuum can becomeunstable due to finite ion temperature gradient. Here, νA is the Alfvén speed, q and R are the safety factor and the major radius of the flux surface, respectively. Recently, it has been shown, with the multiple scale asymptotic technique, that discrete modes may exist in an unstable shear Alfvén continuous spectrum, due to finite ion Larmor radius （FLR） and finite drift-orbit width （FOW） effects in tokamak plasmas which are stable with respect to ideal magnetohydrodynamic （MHD） instabilities .
基金Supported by the National Natural Science Foundation of China（10135020）
文摘In this paper, the electron temperature gradient （ETG） instability and corresponding turbulent transport in toroidal plasmas with negative magnetic shear is studied using the integral eigenvalue equations. The full electron kinetics is considered and the behaviours of the modes and the transport in the parameter regimes close to the instability threshold are emphasized. The fitting formulas of the critical gradient, for negative magnetic shear, are given.
