Modulated ion-acoustic wavepackets in a multi-component dense plasma with Thomas-Fermi distribution

الملخص

Modulated ion acoustic wavepackets have been investigated in a multi-component, dense plasma containing degenerate electrons/positrons, and positive/negative ions. The electrons and positrons assumed to be followed Thomas-Fermi distribution, while the ions considered to be classic. Employing a multi-scale perturbation technique, the nonlinear Schrödinger equation is derived. The criteria for the occurrence of modulational instability of the modulated ion acoustic waves are analyzed. The influences of plasma parameters on the modulational instability and its growth rate have been discussed. The envelope solitons have been discussed as well. The results showed that both modulationally unstable domain and stable domain can be found, depending on the plasma parameters. It is also found that the width of the envelop solitons are significantly modified by related plasma parameters. The present results will be useful in understanding the conditions for modulational instability of ion acoustic waves which are relevant to both space and laboratory dense plasmas.