Barkas Effect in Strongly Magnetized Plasmas

Strongly magnetized plasmas characterized by the gyrofrequency exceeding the plasma frequency exhibit novel transport properties. For example, recent work showed that the friction force on a test charge moving through a strongly magnetized plasma includes components perpendicular to the velocity of the test charge in addition to the normal stopping power component. These works focused on the case that the sign of the test charge is the same as that of the strongly magnetized plasma that it interacts with. Here, we extend the calculation to the case of unlike sign of charges, such as an ion interacting with strongly magnetized electrons. It is found that strong magnetization causes a large Barkas effect, whereby the friction force changes dramatically depending on the sign of the test charge. Good agreement between molecular dynamics simulations and predictions of a generalized Boltzmann kinetic theory are obtained. The combination of the strong magnetization and Barkas effect is found to decrease the parallel electrical resistivity and increase the perpendicular electrical resistivity significantly.