Study of Laser Acceleration of Electrons in a Magnetized Collisionless Plasma

number: 
2555
إنجليزية
department: 
Degree: 
Author: 
Amal Mohammed Kneoy Al-Akashi
Supervisor: 
Dr. Khalid A. Yahya
Dr. Mohammed A. Habeeb
year: 
2010

         A theoretical and computational investigation was carried out in the field of laser-plasma interaction using the Finite Difference Method to study the acceleration of electrons with non-relativistic elocities in a non-magnetized and magnetized collisionless plasmas.First, a (Nd:YAG) laser pulse of  25 fs duration and 5x10  intensity was assumed in the present study.When this laser pulse was allowed to nteract with a stationary electron in vacuum, it was found that the electron is accelerated during the interaction only and returns to stationary state after the laser pulse has passed, in agreement with previous works.
   Also, the interaction of the same laser pulse with a collisionless plasma at electron density n W/cm2 e= 1x10 18  cm  was studied. It was noticed that the energy of the electron during the interaction has reached a maximum value of ~ 1 keV at laserpulse intensity of 5x10 , while the energy of the electron after the interaction reached ~ 15 eV for the same laser pulse intensity.15  W/cm 2 -315   Finally, the interaction of the same laser pulse with a plasma was studied at electron density n e =1x10 18  cm  in the presence of an external magnetic field for the three values of the -3 field strength B= 60 MG, 70 MG and 80 MG. It was found that there is an increase in the acceleration of the electron to reach a maximum energy of ~ 19 keV at a laser pulse intensity of  5x10 15  W/cm and an applied external magnetic field strength of 80 MG during the interaction. However, the electron energy after the interaction reached ~ 3 keV at a laser pulse intensity of 5x10 15  W/cm 2 2  and an applied external magnetic field strength of
70 MG. This is due to a sustainable generated laser wakefield of ~ 2x10  V/cm. Thus, it is concluded that an applied external magnetic field assists the acceleration of the electron and can subsidize for a high laser beam intensity.