A Plasma of Electrons and Ions in Magnetic Field

Let’s say if we place a plasma of electrons and ions in an infinite, homogeneous magnetic field with strength B(t). Then the field strength increases from B(t=0) to a certain level, then the plasma is allowed to relax to equilibrium, then the field strength decreases back to B(t=0), and the plasma is allowed to relax to equilibrium again. How can I modify this process to pump energy mainly into electrons, but not into ions? And how can I modify this process to pump energy mainly into ions, but not into elections?