Filtreler

2019 - 20204
Filtreleri Sıfırla

Ayarlar

Yazar: Demiray, Hilmi × WoS Q: Q4 ×

Arama Sonuçları

Listeleniyor 1 - 4 / 4
  • Küçük Resim
    Yayın
    An approximate wave solution for perturbed KDV and dissipative NLS equations: weighted residual method
    (Işık University Press, 2019-06-21) Demiray, Hilmi
    In the present work, we modified the conventional "weighted residual method" to some nonlinear evolution equations and tried to obtain the approximate progressive wave solutions for these evolution equations. For the illustration of the method we studied the approximate progressive wave solutions for the perturbed KdV and the dissipative NLS equations. The results obtained here are in complete agreement with the solutions of inverse scattering method. The present solutions are even valid when the dissipative effects are considerably large. The results obtained are encouraging and the method can be used to study the cylindrical and spherical evolution equations.
  • Küçük Resim
    Yayın
    On progressive wave solution for non-planar KDV equation in a plasma with q-nonextensive electrons and two oppositely charged ions
    (Işık University Press, 2020) Demiray, Hilmi; El-Zahar, Essam Roshdy; Shan, Shaukat Ali
    In this paper, the ion-acoustic wave is investigated in a plasma with q-nonextensive electrons and two oppositely charged ions with varying masses. These parameters are found to modify the linear dispersion relation and nonlinear solitary structures. The reductive perturbation method is employed to derive modified Korteweg-de Vries (KdV) equation. To solve the obtained governing evolution equation, the exact solution in the planar geometry is obtained and used to obtain an analytical approximate progressive wave solution for the nonplanar evolution equation. The analytical approximate solution so obtained is compared with the numerical solution of the same nonplanar evolution equation and the results are presented in 2D and 3D figures. The results revealed that both solutions are in good agreement. A parametric study is carried out to investigate the effect of different physical parameters on the nonlinear evolution solution behavior. The obtained solution allows us to study the impact of various plasma parameters on the behavior of the nonplanar ion-acoustic solitons. The suitable application of the present investigations can be found in laboratory plasmas, where oppositely charged ions and nonthermal electrons dwell.
  • Küçük Resim
    Yayın
    Modulational instability of three dimensional waves in a plasma with vortex electron distribution
    (Işık University Press, 2019-02-10) Demiray, Hilmi
    In the present work, employing the three dimensional equations of a plasma composed of a cold electron fluid, hot electrons obeying a trapped / vortex-like distribution, and stationary ions, we study the amplitude modulation of an electron-acoustic waves by use of the conventional reductive perturbation method. Employing the field equations with fractional power type of nonlinearity, we obtained the three dimensional form of the modified nonlinear Schrodinger equation as the evolution equation of the same order of nonlinearity. The modulational instability of the homogeneous harmonic solution is investigated and the criteria for the instability is discussed as a function of the obliqueness angle. The numerical calculations show that the critical value of the wave number of the envelop wave increases with the wave number k of the carrier wave and the obliqueness angle gamma.
  • Küçük Resim
    Yayın
    A note on the cylindrical waves with transverse distortion in a plasma with vortex electron distribution
    (Işık University Press, 2020-01-20) Demiray, Hilmi
    In the present work, employing the conventional reductive perturbation method and the nonlinear field equations of a plasma consisting of a cold electron uid, hot electrons obeying a non-isothermal (trapped/vortex-like) distribution and station-ary ions with transverse distortion, we studied the propagation of nonlinear waves in such a plasma medium and obtained the modified CKP equation. Seeking a progressive wave solution to this evolution equation we obtained the exact analytical solution. It is observed that the speed of the solitary wave is directional dependent and the wave front is not circularly cylindrical surface any more.