Relativistic-induced opacity of electron-positron plasmas

Huang, Jian and Weng, S. M. and Murakami, M. and Sheng, Z. M. (2021) Relativistic-induced opacity of electron-positron plasmas. Plasma Physics and Controlled Fusion, 63 (4). 045010. ISSN 0741-3335 (https://doi.org/10.1088/1361-6587/abe0f9)

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Abstract

The interaction of intense electromagnetic waves with electron-positron (e-e+) plasmas is studied by particle-in-cell simulations and theoretical analysis. It is found that an initial underdense e+plasma can become opaque under the irradiation of a relativistically intense laser pulse. The strong ponderomotive force of the relativistic laser pulse and the small mass density of the e-e+ plasma can combine to induce the efficient pile-up of the electrons and positrons at the front of the laser pulse. Therefore, the local plasma density at the laser pulse front increases dramatically and finally the initial underdense e-e+ plasma becomes opaque. This relativistic-induced opacity effect of e-e+ plasmas is opposite to the well-known relativistic-induced transparency effect, in which an initial overdense electron-ion plasma can become transparent to a relativistically intense laser pulse. Further, the significant red shift of reflected lights as well as the efficient generation of energetic positrons are investigated in the relativistic-induced opacity of e-e+ plasmas. This relativistic-induced opacity effect is a peculiar phenomenon in the e-e+plasmas, which may be encountered in the high-energy astrophysical phenomena or in the interactions of intense lasers with matters in the laboratories.

ORCID iDs

Huang, Jian, Weng, S. M., Murakami, M. and Sheng, Z. M. ORCID logoORCID: https://orcid.org/0000-0002-8823-9993;
CORE (COnnecting REpositories)