Department of Physics
Permanent URI for this collectionhttp://localhost:4000/handle/123456789/1932
Browse
3 results
Search Results
Item Energetic electron bunch generation by laser interaction with xenon clusters(AIP, 2018-10) Holkundkar, Amol R.We study the interaction of intense, sub-cycle, and few-cycle laser pulses with xenon clusters for the generation of mono-energetic electron bunches. For this purpose, we used three dimensional, relativistic, molecular dynamics simulations. In this work, we used two mutually perpendicularly polarized (MPP) pulses separated by a finite temporal phase delay. The first pulse is responsible for the generation of electrons by field ionization of atomic clusters. However, the second pulse tends to accelerate the electrons (created by the first pulse) as a bunch. The effect of phase delay, pulse duration, and peak laser intensity on the generation of energetic electron bunches is studied. Under optimum conditions, the electrons are found to be accelerated to energies as high as 2.5 MeV. The feasibility of further acceleration of these electron bunches utilizing laser wakefield acceleration is also explored in this work by treating the accelerated electron bunch by MPP pulses as an initial condition to the nonlinear one-dimensional laser wakefield equations. The rough estimate of the final accelerated electron energies after laser wakefield acceleration has also been madeItem Higher harmonics and attosecond pulse generation by laser induced Thomson scattering in atomic clusters(APS, 2019-08) Holkundkar, Amol R.The generation of higher harmonics of intense lasers and associated attosecond pulses is a field of contemporary interest which promises a variety of applications ranging from the fundamental to applied sciences. In this work, we have probed the interaction of the intense (≳1019 W/cm2) 248 nm laser with Deuterium clusters using classical molecular dynamics simulation. The Thomson scattered radiation emitted by the electrons is considered by using standard Liénard-Wiechert potentials. We have studied the angular distribution of the radiation emitted by electrons and observed that the ponderomotive force exerted by these highly intense laser pulses leaves a very distinct signature of the radiated energy along a particular direction, which in principle has its own diagnostic potential to directly measure the intensities of incident laser pulses. Furthermore, the interaction of lasers with intensities ∼1019–1021 W/cm2 with atomic clusters results in the attosecond burst of energy in form of electromagnetic radiations, which fall under the XUV to soft x-rays regime of electromagnetic spectrum. The parameters of the atomic clusters, e.g., size (number of atoms), atomic species, etc. can be easily controlled experimentally and these in turn, change the number of electrons participating in the interaction process and hence, the properties of Thomson scattered radiation can be tuned accordingly.Item Molecular dynamic simulation for laser–cluster interaction(AIP, 2011-05) Holkundkar, Amol R.A three dimensional relativistic molecular dynamic model for studying the laser interaction with atomic clusters is presented. The model is used to simulate the interaction dynamics of deuterium, argon, and xenon clusters when irradiated by the short and high intensity laser pulses. The interaction of 82 Å argon cluster by 100 fs, 806 nm laser pulse with the peak intensity of 8 1015 W/cm2 is studied and compared with the experimental results. The maximum ion energy in this case is found to be about 200 keV. Ion energies along and perpendicular to laser polarization direction is calculated and asymmetry along laser polarization direction is detected which is further explained on the basis of charge flipping model. The effect of cluster density on the energetics of the laser–cluster interaction is also being studied, which provides a qualitative understanding of the presence of optimum cluster size for maximum ion energies.