نوع مقاله : مقاله پژوهشی

نویسندگان

پژوهشکده پلاسما و گداخت هسته‌ای، پژوهشگاه علوم و فنون هسته‌ای، سازمان انرژی اتمی، صندوق پستی: 51113-14399، تهران- ایران

چکیده

در این پژوهش، شکل‌گیری موج عقبه در برهم­کنش پالس قوی لیزر با گاز با استفاده از نتایج کد شبیه­سازی PIC به­همراه یونیزاسیون بررسی شده و نتایج با حالتی که پالس لیزر در پلاسمای پیش­فرض منتشر می‌شود، مقایسه شده است. نتایج نشان می­دهند که برخلاف نتایج قبلی که به­دلیل ایجاد نوسانات چگالی هنگام یونیزاسیون، به راه­اندازی قوی ناپایداری رامان رو به جلو و به دنبال آن به مدوله شدن قوی پالس لیزر اشاره کرده بودند، اندازه میدان عقبه تولیدی در حالت انتشار پالس لیزر در گاز نسبت به پلاسما، به­شدت به شیب پالس لیزر وابسته است. علاوه بر آن برای پالس‌هایی با شیب تند، این دو مقدار تقریباً یکسان هستند. این در حالی است که برای پالس‌هایی با شیب ملایم‌تر، میدان عقبه در پلاسما دارای مقادیر بزرگ­تری بوده و برای پالس­های با شیب کم­تر، دامنه میدان عقبه در گاز بزرگ­تر می‌باشد.

کلیدواژه‌ها

عنوان مقاله [English]

Investigation of the wakefield generation in the interaction of the intense laser pulse with gas

نویسندگان [English]

  • E. Khalilzadeh
  • M.J. Jafari
  • Z. Dehghany

Plasma and Nuclear Fusion Research School, Nuclear Science and Technology Research Institute, AEOI, P.O. Box: 14399-51113, Tehran, Iran

چکیده [English]

In the present work, the formation of the wakefield during the interaction of intense laser pulse with a gas medium has been investigated by using PIC simulation code, including the ionization process. The results have been compared with those corresponding to the case of the pre-formed plasma medium. Although in previously published works, the strong launch of forwarding Raman's instability was shown to be as a result of plasma density fluctuations during ionization and the subsequent strong laser pulse modulation, our results indicate that the wakefield amplitude in gas in comparison with plasma considerably depends on the laser pulse shape. For laser pulse with a high slope, the amplitude of the wake electric field is quite the same in gas and plasma mediums. However, as the slope of the laser pulse decreases (soft slope), the wakefield is generated with a larger amplitude in the plasma. A further decrease in the laser pulse slope leads to a larger wake electric field in gas than in a plasma environment.

کلیدواژه‌ها [English]

  • Wake field
  • Laser-plasma interaction
  • Pulse rise time
  • Raman instability
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