ناپایداری مدولاسیونی امواج الکترومغناطیسی غیرخطی در توری براگ پلاسمایی

نوع مقاله : مقاله پژوهشی کامل

نویسنده

عضو هیأت علمی/ دانشگاه محقق اردبیلی

چکیده

انتشار غیرخطی امواج الکترومغناطیسی در توری براگ پلاسمایی در نظر گرفته شده است. با استفاده از معادلات ماکسول همراه با مدل سیالی پلاسما و در رژیم نسبیتی ضعیف، دو معادله جفت شده بدست آمد که حاکم بر تحولات پوش امواج پیشرونده و پسرونده در یک پلاسمای سرد نامغناطیده می باشند که چگالی زمینه آن به فرم یک توری براگ مدوله شده است. سپس جوابهای غیرخطی به صورت امواج تخت با دامنه ثابت در نظر گرفته شده و پایداری آنها نسبت به یک اختلال کوچک مورد بررسی قرار گرفته است. وابستگی نرخ رشد و همچنین پنجره ناپایداری به پارامترهای مربوطه سیستم مورد کنکاش قرار گرفته است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Modulational instability of nonlinear electromagnetic waves in plasma Bragg grating

چکیده [English]

The nonlinear propagation of electromagnetic waves in a plasma Bragg grating is considered. In a weakly relativistic regime, by means of the Maxwell’s equations along with a plasma fluid model, two coupled equations are found that govern the evolution of the envelopes of forward and backward propagating waves in a cold unmagnetized plasma undergoing an ambient density modulation in the form of gratings. Then, the nonlinear plane wave solutions with constant amplitude are obtained and the stability of them against a small perturbation is investigated. The dependence of the growth rate and instability window on relevant parameters of the system is addressed.

کلیدواژه‌ها [English]

  • Modulational instability
  • Electromagnetic waves
  • Plasma Bragg grating
 
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