Radiative activity of magnetic white dwarf undergoing Lorentz-force-driven torsional vibrations

TL;DR

This paper investigates how magnetic white dwarfs undergoing Lorentz-force-driven torsional vibrations can convert vibrational energy into magneto-dipole radiation, with period elongation linked to magnetic field decay.

Contribution

It demonstrates the mechanism of energy conversion from torsional vibrations to radiation in magnetic white dwarfs and relates period changes to magnetic field decay.

Findings

White dwarfs can emit magneto-dipole radiation due to torsional vibrations.

Period lengthening of emission is caused by magnetic field decay.

Vibration energy can be converted into observable electromagnetic radiation.

Abstract

We study radiative activity of magnetic white dwarf undergoing torsional vibrations about axis of its own dipole magnetic moment under the action of Lorentz restoring force. It is shown that pulsating white dwarf can convert its vibration energy into the energy of magneto-dipole emission, oscillating with the frequency equal to the frequency of Alfv\'en torsional vibrations, provided that internal magnetic field is decayed. The most conspicuous feature of the vibration energy powered radiation in question is the lengthening of periods of oscillating emission; the rate of period elongation is determined by the rate magnetic field decay.