To properly understand the physics of Ap and Bp stars it is particularly important to identify the origin of their magnetic fields. For that, an accurate knowledge of the evolutionary state of stars that have a measured magnetic field is an important diagnostic. Previous results based on a small and possibly biased sample suggest that the distribution of magnetic stars with mass below 3M⊙ in th...

Arc plasmas have promising applications in many fields, and exploring their properties is of interest. This research paper presents detailed pressure-based finite volume simulations an argon arc. Simulations the free-burning arc show good agreement with experiment. We observe interesting phenomenon that concentrates intensively a high-frequency alternating longitudinal magnetic field. different...

We present a detailed model for the magnetic field of the chemically peculiar star HD 119419 consistent with five different kinds of observational constraint: mean longitudinal field, crossover, mean quadratic field, projected equatorial velocity and stellar radius. The stellar surface presents a complex magnetic structure originated by a 17 kG dipole superposed to a 48 kG quadrupole, and inclu...

A study is made of the influence of the longitudinal magnetic field and density inhomogeneity on the supersonic shear flow instability at the magnetospheric tail boundary. It is shown that the most unstable are slow oblique (3D) disturbances, with a phase velocity approaching at a sufficiently large angle (with respect to the flow direction) the magnetosonic velocity. Their growth rate and spec...

We have obtained a time series of 81 high-cadence circular polarization observations of the rapidly oscillating Ap star HD 24712 with the new ESPaDOnS spectropolarimeter at CFHT. We used the high-S/N, high-resolution Stokes I and V spectra to investigate possible variation of the mean longitudinal field over the pulsation cycle in this roAp star. Our multiline magnetic field and radial velocity...

Two-stream instability in pulsar magnetospheres generates longitudinal waves, which fall in the superluminal part of the dispersion curve due to stimulated scattering. A superluminal longitudinal wave propagating in a curved magnetic field turns into an electromagnetic wave and may escape from plasma in the form of an ordinary transverse wave. However, this wave may go to the subluminal part of...