159 research outputs found
Efficiency of the centrifugally induced curvature drift instability in AGN winds
For studying how the field lines are twisting nearby the light cylinder
surface, which provides the free motion of AGN winds through the mentioned
area, the investigation of the centrifugally driven curvature drift instability
is presented. Studying the dynamics of the relativistic MHD flow close to the
light cylinder surface, by applying a single particle approach based on the
centrifugal acceleration, the dispersion relation of the instability is derived
and analytically solved. Considering the typical values of AGN winds, it is
shown that the time scale of the curvature drift instability is much less than
the accretion process time scale, indicating that the present instability is
very efficient and might strongly influence processes in AGN plasmas.Comment: 7 pages, 7 figure
Rotationally-driven VHE emission from the Vela pulsar
The recent detection of pulsed -ray emission from the Vela pulsar in
the to 100 GeV range by H.E.S.S. promises an important potential to
probe into the very high energy (VHE) radiation mechanisms of pulsars. The
recent detection of pulsed -ray emission from the Vela pulsar in the
to 100 GeV range by H.E.S.S. promises an important potential to probe
into the very high energy (VHE) radiation mechanisms of pulsars. We analyze
achievable particle energies in the magnetosphere of the Vela pulsar, and
calculate the resultant emission properties. Inverse Compton up-scattering of
thermal photons from the surface of the star is shown to lead a pulsed VHE
contribution reaching into the TeV regime with spectral characteristics
compatible with current findings. If confirmed by further observations this
could be the second case where rotationally-driven processes turn out to be
important to understand the VHE emission in young pulsars.Comment: 5 pages, 2 figure
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