The chirped pulse amplification technique has opened new horizons for investigating the physics of laser-matter interaction at extremely high laser intensities (> 1018 W/cm2). At these intensities, the plasma becomes so hot and energetic that relativistic effects become important. Such plasmas are of interests in areas of physics such as nuclear physics, medical physics, radiography studies, high energy astrophysics and accelerator physics. Current focus of the group is to study such interactions for the generation of compact table-top 200 MeV proton accelerator. One such acceleration scheme, called radiation pressure acceleration (RPA), involves irradiation of an intense short-pulse laser on a thin foil of thickness about 100s nm. In this scheme, the radiation pressure associated with an electromagnetic field accelerates the particles to 100s MeV within a distance of few microns. For example, in the figure below the laser (shown by red-black contour lines) pushes the thin target (shown in green) leading to acceleration of protons to close to 100 MeV in 5 micron distance.

Mathematical modeling of plasma involves self-consistent evolution of electromagnetic fields and plasma particles. The charge particles in plasma respond to electric and magnetic fields whereas fields themselves change to currents and charge densities associated with plasma species. Most complete description of such a system can be obtained through Particle-In-Cell (PIC) simulations which solve Vlasov-Maxwell/Vlasov-Poisson system of equations. The group is interested in development of numerical simulation tools for such systems. We have already developed a 2D electromagnetic relativistic PIC code AGASTHII-py for intense laser-plasma interaction. We are actively working on extending this code to incorporate novel algorithms which will lead to computationally efficient modeling of plasma.

Low temperature plasmas have wide range of applications ranging from semiconductor fabrication industry to electric propulsion devices. When such plasmas are magnetized, kinetic instabilities such as electron cyclotron drift instability, modified two stream instability etc. are excited. Such instabilities can not be explained with the standard fluid description of the plasma. The micro-turbulence caused by such instabilities can significantly impact the performance of devices in which such plasmas are used. We are interested in understanding the basic physics of such instabilities through PIC simulations.