الفهرس | Only 14 pages are availabe for public view |
Abstract To summarize, the modulational (in)stability of the envelope IAWs in strongly coupled UNPs composed of ions uid and nonMaxwellian electron have been investigated. A reductive perturbation technique is used to derive the NLSE, and exact expressions for the coefcients of the dispersion and nonlinear terms were obtained. These have allowed us to study the modulational (in)stability prole of the IAWs in various parameter regimes. The critical wavenumber kc, which indicates where the modulational instability sets in, has been determined for various regimes. This study shows that the existence of nonMaxwellian electron in UNPs introduces new features for the nonlinear wave modulation which do not exist in traditional plasmas (i.e., i < 1). The effects of the nonthermal parameter or the nonextensive parameter q; and the effective temperature ratio on the critical wavenumber kc are studied. The ndings of our present investigation can be pointed out as follows: 1. For low values of the wavenumbers, increasing the nonthermal parameter would lead to cringe kc until approaches to its critical value c, then further increase of beyond c would enhance the values of kc. For higher values of 88 the wavenumbers, the increase of would lead to a decrease of kc. 2. The dependence of kc on the nonextensive parameter q is investigated. It is found that for low wavenumber, kc decreases with increasing q in the range q < 0, then further increase of q > 0 would lead to enhance the value of kc. For higher wavenumber, the increase of q would lead to an increase of kc. 3. Augmenting the temperature ratio would lead to the reduction of kc for all values of the wavenumber. 4. Within the modulational unstable envelope pulse region, it is possible for a random perturbation of the amplitude to grow and may thus lead to generation of ion-acoustic rogue waves. 5. The dependence of the rst- and second-order rational solutions proles on the plasma parameters is numerically examined. It is found that the envelope rogue wave amplitudes have complex behavior with increasing and q. However, the increase of the effective temperature ratio and the carrier wavenumber k reduce the envelope rogue wave amplitudes. Near kc; the rogue wave amplitude becomes higher, but the amplitude shrinks whenever we stepped away from kc. |