Speaker
Amita Das
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/I5.214.pdf
Novel mechanism of Magnetic field generation in a finite beam plasma
system
Amita Das1 , Atul Kumar1 , Chandrasekhar Shukla1 , Ratan Kumar Bera1 , Deepa Verma1 ,
Devshree Mandal1 , Ayushi Vashistha1 , Bhavesh Patel1 , Predhiman Kaw1 ,
Y. Hayashi2 , K. Tanaka3 ,
G. Ravindra Kumar4 and Amit Lad4
1 Institute for Plasma Research, Bhat Gandhinagar, India
2 Graduate School of Engineering, Osaka University, Suita, Osaka 565-0871 Japan
3 Extreme Laser Infrastructure-Nuclear Physics 30 Reactorului, PO Box MG-6, Bucharest
Magurele 077125 Romania
4 Tata Institute for Fundamental Research 1 Homi Bhabha Road, Mumbai 400005, India
When an energetic electron beam propagates in a plasma it produces return shielding currents
from background electrons. The combination of forward and return shielding currents are con-
ventionally believed to be unstable to the Weibel instability which generates magnetic field at
the electron skin depth scales. We have demonstrated by Particle - In - Cell (PIC) as well as fluid
simulations, laser plasma experiments and analytic theory that a hitherto unknown instability
(distinct from both Weibel and Kelvin Helmholtz ) is excited in the beam plasma system where
the beam has a finite transverse size. This instability is responsible for the generation of mag-
netic fields at scales comparable to the transverse beam dimension which can be much longer
than the electron skin depth scale. This counter-intuitive result arises due to radiative leakage
associated with finite beam boundaries which is absent in the infinite and/or periodic systems
considered in all earlier simulations.
