  The excitation of electrostatic waves in plasma by laser electromagnetic
pulse is important as it provides a scheme by which the power from the laser
electromagnetic (EM) field can be transferred into the plasma medium. The paper
presents a fundamentally new ponderomotive pressure-driven mechanism of
excitation of electrostatic waves in an overdense magnetized plasma by a finite
laser pulse. Particle-in-cell (PIC) simulations using the EPOCH-4.17.10
framework have been utilized for the study of a finite laser pulse interacting
with a magnetized overdense plasma medium. The external magnetic field is
chosen to be aligned parallel to the laser propagation direction. In this
geometry, the electromagnetic wave propagation inside the plasma is identified
as whistler or R and L waves. The group velocity of these waves being
different, a clear spatial separation of the R and L pulses are visible. In
addition, excitation of electrostatic perturbation associated with the EM
pulses propagating inside the plasma is also observed. These electrostatic
perturbations are important as they couple laser energy to the plasma medium.
The excitation of electrostatic oscillations are understood here by a
fundamentally new mechanism of charge separation created by the difference
between the ponderomotive force (of the electromagnetic pulse) felt by the two
plasma species, viz., the electrons and the ions in a magnetized plasma.
