On the possible observational manifestation of supernova shock impact on the neutron star magnetosphere

Impact of supernova explosion on the neutron star magnetosphere in a massive binary system is considered. The supernova shock striking the NS magnetosphere filled with plasma can lead to the formation of a magnetospheric tail with significant magnetic energy. The magnetic field reconnection in the current sheet formed can convert the magnetic energy stored in the tail into kinetic energy of accelerated charged particles. Plasma instabilities excited by beams of relativistic particles can lead to the formation of a short pulse of coherent radio emission with parameters similar to those of the observed bright extragalactic millisecond radio burst (Lorimer et al. 2007).Comment: 8 pages, Astron. Lett. in pres

Induced scattering of short radio pulses

Effect of the induced Compton and Raman scattering on short, bright radio pulses is investigated. It is shown that when a single pulse propagates through the scattering medium, the effective optical depth is determined by the duration of the pulse but not by the scale of the medium. The induced scattering could hinder propagation of the radio pulse only if close enough to the source a dense enough plasma is presented. The induced scattering within the relativistically moving source places lower limits on the Lorentz factor of the source. The results are applied to the recently discovered short extragalactic radio pulse.Comment: submitted to Ap

Evolution and stability of a magnetic vortex in small cylindrical ferromagnetic particle under applied field

The energy of a displaced magnetic vortex in a cylindrical particle made of isotropic ferromagnetic material (magnetic dot) is calculated taking into account the magnetic dipolar and the exchange interactions. Under the simplifying assumption of small dot thickness the closed-form expressions for the dot energy is written in a non-perturbative way as a function of the coordinate of the vortex center. Then, the process of losing the stability of the vortex under the influence of the externally applied magnetic field is considered. The field destabilizing the vortex as well as the field when the vortex energy is equal to the energy of a uniformly magnetized state are calculated and presented as a function of dot geometry. The results (containing no adjustable parameters) are compared to the recent experiment and are in good agreement.Comment: 4 pages, 2 figures, RevTe