The characteristic time of (incompressible) resistive modes in the neighbourhood of an X-point in the absence of external forcing is found to scale, when normalized on the Alfven time, as (epsilon/\n epsilon\)(-1) with epsilon the ratio between the Alfven and the resistive time. In X-point configurations with oblique separatrices, the mode time-scale becomes faster as the angle between the separatrices decreases. When this angle becomes of the order of \ln epsilon\(-1), the (epsilon \ln \epsilon\)(-1) scaling breaks down. Similar to the case of a resonant magnetic line configuration, resistive modes can be driven unstable by the inhomogeneity of the current density.
RESISTIVE MODES AT A MAGNETIC X-POINT
PEGORARO, FRANCESCO
1995-01-01
Abstract
The characteristic time of (incompressible) resistive modes in the neighbourhood of an X-point in the absence of external forcing is found to scale, when normalized on the Alfven time, as (epsilon/\n epsilon\)(-1) with epsilon the ratio between the Alfven and the resistive time. In X-point configurations with oblique separatrices, the mode time-scale becomes faster as the angle between the separatrices decreases. When this angle becomes of the order of \ln epsilon\(-1), the (epsilon \ln \epsilon\)(-1) scaling breaks down. Similar to the case of a resonant magnetic line configuration, resistive modes can be driven unstable by the inhomogeneity of the current density.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
