Orientation phenomena for electron–ion collisional excitations in a classical nonideal plasma

Abstract

Orientation phenomena for direct 1s → 2p_±1 excitations in electron–hydrogenic-ion collisions are investigated in a classical nonideal plasma. An effective pseudopotential model taking into account plasma-screening and collective effects is applied to describe the interaction potential in a nonideal plasma. The orientation parameter for direct 1s → 2p_±1 excitations in a nonideal plasma is obtained as a function of the impact parameter, the nonideal-plasma parameter, the Debye length, and the projectile energy. The result shows that the nonideal effect reduces the propensity of the 1s → 2p₋₁ transition. It is also found that the nonideal effect on the orientation parameter increases with increasing projectile energy.