A Numerical Model for Accretion in Intermediate Polars with Dipolar Magnetic Fields

TL;DR

This paper presents a 3D numerical model for accretion in magnetic white dwarfs, accounting for dipolar magnetic fields, turbulence, and radiative processes, revealing the formation of magnetospheres and accretion columns.

Contribution

It introduces a novel 3D MHD-based model for accretion in intermediate polars with inclined dipole magnetic fields, including magnetic diffusion and radiative effects.

Findings

Magnetosphere forms around the white dwarf.

Accretion occurs via curtain-like columns.

Arc-shaped energy release zones develop on the surface.

Abstract

A three-dimensional numerical model for an accretion process investigation in the magnetosphere of a white dwarf in magnetic cataclysmic variables is developed. The model assumes that the white dwarf has a dipole magnetic field with its symmetry axis inclined to the rotation axis. The model is based on the equations of modified MHD, that describe the mean flow parameters in the wave MHD turbulence. Diffusion of the magnetic field and radiative heating and cooling are taken into account. The suitability of the model is confirmed by modeling the accretion in a typical intermediate polar. The computations show that a magnetosphere forms around the accretor, with the accretion occurring via columns. The accretion columns have a curtain-like shape, and arc-shaped zones of energy release form on the surface of the white dwarf in the magnetic poles area as a result of the matter infall.