SHIELDING OF TEST CHARGE PROJECTILES IN PLASMA

Abstract

In this work, we have studied the shielding potential (41) of a test charge in plasma by using the kinetic theory approach. We found that for slowly moving test charge (compared with the thermal velocity of ions and electrons), the test charge is shielded both by electrons and Ions. For a fast moving test charge (compared with the velocity of electrons), no Shielding was observed. For a test charge moving with the intelmediate speed (greater than ions but less chan electrons thermal velocity), only electrons were found to take part in the shielding. Next, we have calculated the shielding potential in dusty plasma by using the linear dielectric theory. The electrostatic potential for two projectiles is computed for different values ofKo (normalize effective wave number) and R (the separation between the two projectiles) retaining two ion correlation effects and then it is compared with that of single ion projectile case. Further. we extend it for multi component plasma. Here we also employ the test charge approach to calculate the shielding potential. The constit\lents of multi-component plasma are the Boltzmarm distributed electrons, mobile positive and negative ions, and immobile positive/negative dust particles. The shielded pot~ntia( is found to be modified due to the presence of negative ions in plasma. We have calculated the Debye screening and wake potential. It is found that the presence of negative ions significantly modify the dust-ion-acoustic speed.