Ultrarelativistic spin-polarized plasma

Ultrarelativistic plasma is an extreme state associated with strong field QED effects such as radiation reaction, gamma-ray photon emission, and positron generation. The ultrarelativistic plasma can be polarized due to radiative spin flips within high-energy photon emission. Considering spin is an intrinsic property of electrons, spin-polarized plasma might open a new avenue for the controlled generation of polarized electron beams. The latter has crucial applications in material science, nuclear structure measurements, and fundamental high-energy physics. Additionally, due to the new degree of freedom of information carried by the spin signal, ejected polarized particles can also be used to retrieve transient plasma dynamics that are hard to achieve by conventional diagnostics.

This talk will focus on i) how ultrarelativistic spin-polarized plasma is produced and ii) the correlation between transient dynamics and plasma’s spin-polarization signal. By inspecting unsymmetric electron polarization, we identified a nontrivial magnetic island structure accompanied by current vortexes. In addition, we found that the angular polarization pattern of emitted gamma photons could facilitate deciphering electrons’ in-situ acceleration status. Furthermore, we elucidated that electron polarization in current filamentation instabilities is correlated with the filament’s nonlinear transverse motion.