Date:
Tue, 04/11/201412:30-13:30
Location:
Kaplun building, Room No. 200
Lecturer: Dr. David Tsiklauri
Affiliation: Queen Mary University of London
Abstract:
The main unsolved problems in space/solar
plasmas will be briefly reviewed, followed by
a more detailed discussion of the effect
of plasma inhomogeneity on particle acceleration
and associated radio emission generation.
Extensive particle-in-cell simulations of fast
electron beams injected in a background
magnetised plasma with a decreasing density
profile along the magnetic field were carried out.
These simulations were intended to further shed
light on a newly proposed mechanism for the
generation of electromagnetic waves in type III
solar radio bursts [1]. Here recent progress
in an alternative to the plasma emission model
using Particle-In-Cell, self-consistent
electromagnetic wave emission simulations
of solar type III radio bursts will be presented.
In particular, (i) Fourier space drift (refraction)
of non-gyrotropic electron beam-generated
wave packets, caused by the density gradient [1,2],
(ii) parameter space investigation of numerical
runs [3], (iii) concurrent generation of whistler
waves [4] and separate problems of (iv) electron
acceleration by Langmuir waves in a background
magnetised plasma with an increasing density
profile along the magnetic field [5] and (v) electron
acceleration by dispersive Alfven waves
in a plasma with density inhomogeneity across
the magnetic field will be presented.
In all considered cases the density
inhomogeneity-induced wave refraction plays
a crucial role.
[1] D. Tsiklauri, Phys. Plasmas 18, 052903 (2011)
[2] H. Schmitz, D. Tsiklauri, Phys. Plasmas 20,
062903 (2013)
[3] R. Pechhacker, D. Tsiklauri, Phys. Plasmas 19,
112903 (2012)
[4] M. Skender, D. Tsiklauri, Phys. Plasmas 21,
042904 (2014)
[5] R. Pechhacker, D. Tsiklauri, Phys. Plasmas 21,
012903 (2014)
[6] D. Tsiklauri, Phys. Plasmas 19, 082903 (2012)
Additional details of the upcoming Astrophysics'
seminars can be found on the following link.
האירוע הזה כולל שיחת וידאו ב-Google Hangouts.
הצטרף: https://hangouts.google.com/hangouts/_/mail.huji.ac.il/tba-dr-david?hceid=bWFpbC5odWppLmFjLmlsX2c0czhydDlpcmhwZzRvdGNybWIzZGFqcjdvQGdyb3VwLmNhbGVuZGFyLmdvb2dsZS5jb20.h8kmlog2jeuhh0q4hsojgohnn4&hs=121