Speaker
Amulya Kumar Sanyasi
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P2.4008.pdf
Demonstration of Loss Cone Induced Quasi-Longitudinal (QL) Whistlers
in Large Laboratory Plasma of LVPD
A. K. Sanyasi1, L. M. Awasthi1, Prabhakar Srivastav1, P. K. Srivastava1, R. Sugandhi1, S. K.
Mattoo1, D. Sharma1, R. Singh2, R. Paikaray3 and P. K. Kaw
1
Institute for Plasma Research, Gandhinagar 382428, India
2
Advance Technology Centre, NFRI, Daejeon, South Korea
3
Ravenshaw University, Cuttack – 753001, India
E-mail: amulya@ipr.res.in
Abstract
Whistler turbulence observed in earth’s magnetosphere has free energy source lies in
energetic electrons, electron beams, anisotropies in temperature and electron distribution
function, density gradients, loss cone etc. and is responsible for the precipitation of energetic
electrons into the ionosphere. This has been observed that when pole bound electrons get
trapped in the earth’s magnetic field and suffers loss cone instability, which results in the
excitation of Quasi-Longitudinal (QL) whistlers at large oblique angles.
We report experimental observation of loss cone driven Quasi-Longitudinal (QL)
whistlers in a laboratory plasma excited by the reflected electrons from a magnetic mirror.
The QL whistler propagate highly obliquely ( θ = tan −1 (k ⊥ / k || ) ≈ 87 0 ) in a broad band of
40kHz < f ≤ 80 kHz with k ⊥ ~ 1.4 cm −1 and k || ~ 0.06cm −1 respectively. It exhibits strong
correlation between density and magnetic field fluctuations ( , = −0.9), and interestingly
it shows a continuous variation of wave polarization with frequency. We have compared
experimental observations with numerical results obtained from the theoretical models of
Sharma et al. [1], Olga et al. [2] and Quasi Longitudinal (QL) whistlers by Henry G. Booker
et al., [3] and found a good agreement between them. This is probably first laboratory
demonstration of QL whistlers and detailed results on it will be presented in the conference
[4].
References
[1] R. R. Sharma and Loukas Vlahos, The Astrophysical Journal 280, 405(1984).
[2] O. P. Verkhoglyadova et. al., J. Geophys. Res. 115, A00F19 (2010).
[3] Henry G. Booker and Rolf B. Dyce, Radio Science Journal of Research NBS/ USNC-URSI, Vol.
69D, No. 4, April 1965.
[4] A. K. Sanyasi, L. M. Awasthi, P. K. Srivastava, S. K. Mattoo, D. Sharma, R. Singh, R. Paikaray
and P. K. Kaw, Phys. Plasmas 24, 102188 (2017).
