Optical probing of magnet-induced transparent over-dense plasma in a whistler mode

Abstract

For the first time, optical probing of the highly magnetized over-dense plasma in a whistler mode is theoretically investigated, where the over-dense plasma becomes magnet-induced transparent (MIT) for right hand circularly polarized laser when the electron cyclotron frequency is higher than laser frequency. Applications of the popular optical diagnostics technologies (i.e., absorption, interferometry, shadowgraphy, and schlieren imaging) in the MIT plasma are studied in the measurement of plasma density, temperature, and strength of magnetic field. The “normal” Faraday rotation is expanded to region of B > 1 (B is the dimensionless magnetic field) for both over-dense plasma (n > 1, n is the dimensionless plasma density) and under-dense plasma (n < 1). For probing laser with higher intensity as to be able to heat up plasma collisionally, the power transmission is increased and intense laser is found to deposit more energy in the region of higher plasma density or weaker magnetic field.