Dynamical feedback of the curvature drift instability on its saturation process

¹ E. Kharadze Georgian National Astrophysical Observatory, Chavchavadze State University, Kazbegi str. , 0106 Tbilisi, Georgia e-mail: [z.osmanov;d.shapakidze;g.machabeli]@astro-ge.org
² Javakhishvili State University, Chavchavadze str. , 0179 Tbilisi, Georgia

Received: 19 March 2009
Accepted: 27 May 2009

Abstract

Aims. We investigate the reconstruction of pulsar magnetospheres close to the light cylinder surface to study the curvature drift instability (CDI) responsible for the twisting of magnetic field lines in the mentioned zone. The influence of plasma dynamics on the saturation process of the CDI is studied.

Methods. On the basis of the Euler, continuity, and induction equations, we derive the increment of the CDI and analyze parametrically excited drift modes. The dynamics of the reconstruction of the pulsar magnetosphere is studied analytically.

Results. We show that there is a possibility of a parametrically excited rotational-energy pumping-process in the drift modes. It is indicated by the generation of a toroidal component of the magnetic field that transforms the field lines into such a configuration, in which plasma particles do not experience any forces. At this stage, the instability process saturates and the further amplification of the toroidal component to the magnetic field lines is suspended.