Magnetized relativistic electron–ion plasma expansion

• Relativistic magnetized electron–ion plasma expansion is studied.
• Fluid Equations are solved using a self-similar approach.
• Higher conversion of Poynting energy is observed.
• Break-down of quasi-neutrality is associated to small magnetization.

The dynamics of relativistic laser-produced plasma expansion across a transverse magnetic field is investigated. Based on a one dimensional two-fluid model that includes pressure, enthalpy, and rest mass energy, the expansion is studied in the limit of λD (Debye length)≤RLλD (Debye length)≤RL (Larmor radius) for magnetized electrons and ions. Numerical investigation conducted for a quasi-neutral plasma showed that the σ parameter describing the initial plasma magnetization, and the plasma β   parameter, which is the ratio of kinetic to magnetic pressure are the key parameters governing the expansion dynamics. For σ≪1σ≪1, ion's front shows oscillations associated to the break-down of quasi-neutrality. This is due to the strong constraining effect and confinement of the magnetic field, which acts as a retarding medium slowing the plasma expansion.