Rogue Waves in Multi-Ion Cometary Plasmas
- PDF / 2,137,626 Bytes
- 8 Pages / 612 x 792 pts (letter) Page_size
- 66 Downloads / 190 Views
PACE PLASMA
Rogue Waves in Multi-Ion Cometary Plasmas1 G. Sreekalaa*, M. Manesha, T. W. Neethub, V. Anua, S. Sijoa, and C. Venugopala a
School of Pure and Applied Physics, Mahatma Gandhi University, Priyadarshini Hills, Kottayam, Kerala, 686560 India b Department of Physics, C. M. S. College, Kottayam, Kerala, 686001 India *e-mail: [email protected] Received October 25, 2016; in final form, March 15, 2017
Abstract—The effect of pair ions on the formation of rogue waves in a six-component plasma composed of two hot and one colder electron component, hot ions, and pair ions is studied. The kappa distribution, which provides an unambiguous replacement for a Maxwellian distribution in space plasmas, is connected with nonextensive statistical mechanics and provides a continuous energy spectrum. Hence, the colder and one component of the hotter electrons is modeled by kappa distributions and the other hot electron component, by a q-nonextensive distribution. It is found that the rogue wave amplitude is different for various pair-ion components. The magnitude, however, increases with increasing spectral index and nonextensive parameter q. These results may be useful in understanding the basic characteristics of rogue waves in cometary plasmas. DOI: 10.1134/S1063780X18010154
1. INTRODUCTION “Rogue wave” is the name given, by oceanographers, to isolated large-amplitude waves that occur more frequently than expected for normal, Gaussiandistributed statistical events. Rogue waves have become the focus of intense research in the last decade mainly because they are perceived responsible for many maritime disasters. The first measurement of rogue waves in the open ocean was made on an oil platform in Norway in 1995 [1], which confirmed that rogue waves are, indeed, a reality. Currently four to five competing hypotheses exist for rogue wave generation [2]. Among these, a possible mechanism for the formation of rogue waves is the modulation instability (MI) [3], which is a universal phenomenon that occurs in many physical areas, such as optics [4], hydrodynamics [5], and even biology [6]. MI is one in which a plane wave solution is unstable against longitudinal perturbations. An experimental observation of the MI of a monochromatic ion acoustic wave was reported by Watanabe [7]. Also, Shats [8], in his study of capillary rogue waves, observed that a high level of phase coupling in four-wave interactions supports the hypothesis that MI is a key ingredient in rogue wave generation. An experimental study on super rogue waves [9] showed that rogue waves can also develop from very calm and apparently safe sea waters. These results had a significant impact on studies of extreme ocean waves and related studies in other disciplines concerned with 1 The article is published in the original.
waves in nonlinear dispersive media, such as optics, plasma physics, and super fluidity. Thus, rogue waves are ubiquitous in nature and appear in a variety of contexts. Besides water waves, they have been recently reported in liquid helium [10],
Data Loading...
