Stochastic particle transport in a magnetic island due to electrostatic drift waves

Abstract

The effect of poloidally mode coupled, ballooning type electrostatic drift waves on a magnetic island has been studied both analytically and numerically. It has been shown quantitatively that particle orbits become stochastic and their behavior can be a possible candidate for the radial plasma transport across a magnetic island of a tokamak. The transport is significant in that it takes place even when the flux surface is not destroyed. The mechanism of the stochasticity generation is understood as an overlapping of secondary islands caused by resonance between periodic particle motions in the magnetic island and Fourier modes of E×B drift due to the electrostatic drift waves. The diffusion process perpendicular to magnetic surface has been analyzed by approximating the distribution to the Gaussian type. In addition, local diffusion process in the vicinity of Kolmogorov, Arnold, and Moser surfaces has been discussed.

Resistive wall tearing mode generated finite net electromagnetic torque in a static plasma

“…The tearing mode can lead to the deterioration of the confinement, mode locking to the external resistive wall, and plasma disruption. [1][2][3] The onset of the neoclassical tearing mode (NTM) provides a limitation for achievable b (the ratio of the averaged plasma pressure to the magnetic pressure). It is known that the favorable averaged curvature of the equilibrium magnetic field has strong stabilization effect on the tearing mode.…”

Tearing mode analysis in tokamaks, revisited

“…2,3 In resistive MHD, tearing mode stability is determined by a parameter delta prime (⌬Ј), which was first defined by Furth et al; 4 a positive ⌬Ј implies instability. Recently, ⌬Ј was measured in the Tokamak Test Fusion Reactor ͑TFTR͒ supershot plasma experiments through an analysis of electron temperature fluctuations.…”

Chaotic transport in Hamiltonian systems perturbed by a weak turbulent wave field

“…The standard methods to integrate the equations of motion containing a large number of fast-oscillating terms require very long computational times [27]. Therefore, different computational methods have been proposed to overcome these difficulties.…”

“…These models are widely used to study the particle transport caused by turbulent fields in fusion plasmas (see, e.g., Refs. [26][27][28][29][30][31][32][33][34][35] and references therein) and the transport cosmic rays in heliosphere (see Refs. [7,36,37] and references therein).…”

“…Particularly, in Refs. [27,28,32,33] the test particle models are used to explore the effect of low and reversed magnetic shear on the radial transport of field lines and particles in the presence of magnetic and electrostatic perturbations.…”