Fig. 5. Scenario for the generation of LP γ-rays by an ultrastrong LP laser pulse interacting with a conical Au target filled with an NCD hydrogen plasma[65]
Fig. 6. (a) The schematic for generation of linearly polarized gamma-photons with angular spiral tendency from a near-critical density plasma irradiated by a circularly polarized ultrastrong laser pulse. (b) The linear polarization (LP) orientation is along the azimuthal direction. (c) For an accelerating electron, there is a counter-clockwise spiral tendency in the angular distribution of gamma-photon LP orientation. (d) For a decelerating electron, there is a clockwise spiral tendency in the angular distribution of gamma-photon LP orientation. (c) and (d) are for the analytically predicted results, while (e) and (f) are for the corresponding simulation results[69]