Speaker
Ivan Tsymbalov
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P4.2004.pdf
Hybrid SRS-TPD instability in inhomogeneous femtosecond laser plasma
I.N. Tsymbalov1, K.A. Ivanov1, S.A. Shulyapov1, D.A. Gorlova1, A. M. Sen’kevich1, R.V.
Volkov1, A.B. Savel'ev1, A.V. Brantov2, V.Yu. Bychenkov2
1
Faculty of Physics and International Laser Center M.V. Lomonosov Moscow State
University Moscow, Russia
2
P.N. Lebedev Physical Institute Russian Academy of Sciences Moscow, Russia
Electron acceleration in femtosecond laser plasma with scalelength L/λ~1 is due to nonlinear
plasma wave excitation [1]. Optimization of high energy electrons generation requires study
of nonlinear laser-plasma interaction and wave excitation. Radiation scattered by waves
carries information about their frequencies, wave numbers and space localization and can be
used for plasma wave diagnostics. Studies of instability in femtosecond plasma have already
been carried out in papers [2,3], a feature of this work is the short plasma gradient (L/λ~1)
and subrelativistic intensities of the laser pulse.
The PIC simulation showed that the main feature of the oblique incidence laser pulse
interaction with short plasma gradient is refraction, which leads to the appearance of new
components in the spatial spectrum. So, the instability pump wave should now be considered
as a sum of plane waves, and this leads to the appearance of new features for instability
growth rate. The analysis of electromagnetic fields showed that in addition to the
electrostatic component in the ponderomotive forces corresponding to the TPD, there is an
electromagnetic component corresponding to SRS. SRS and TPD have a common plasma
wave. This agrees with the observed values of the plasmon wave vector kx=1.1-1.6k0 [4] The
scattering of the fundamental wave by plasma generates a radiation source with an even
broader spectral ky component and a rather narrow kx component, which determines the
angular distributions of the scattered radiation at frequencies 3/2ω and 1/2ω. The angular
distributions of 3/2ω radiation from PIC simulation are in good agreement with the
experimental data.
[1] K. Ivanov, I. Tsymbalov, S. Shulyapov, D. Krestovskikh, A. Brantov, V.Y. Bychenkov, R. Volkov, and A.
Savel’ev, Phys. Plasmas 24, 063109(2017)
[2] L. Veisz, W. Theobald, T. Feurer, H. Schillinger, P. Gibbon, R. Sauerbrey, and M. S. Jovanovic, Phys.
Plasmas 9, 3197 (2002).
[3] A. Tarasevitch, C. Dietrich, C. Blome, K. Sokolowski-Tinten, and D. von der Linde, Phys. Rev. E 68,
026410 (2003)
[4] B. Quesnel, P. Mora, J.C. Adam, A. Heron, and G. Laval, Phys. Plasmas 4, 3358 (1997).
