Magnetic field gradient-controlled plasma tuning in capacitively coupled discharges via electron beam injection

This study employs 1D particle-in-cell/Monte Carlo collision simulations to systematically investigate the modulation of capacitively coupled plasma by a unidirectional electron beam under tunable magnetic field gradients. The results reveal a remarkable sensitivity of electron beam injection to both the orientation and intensity of the magnetic field gradient, enabling precise tailoring of plasma properties. Critically, the contribution of injected electrons to the discharge is maximized when their cyclotron radius matches the electrode gap, yielding peak plasma density. Furthermore, while ion bombardment energy remains stable under optimal beam injection, the ion flux exhibits significant modulation, demonstrating a decoupling between energy and flux control. These findings establish magnetic field gradients as a powerful tool for real-time plasma tuning in applications requiring dynamic control of density and ion flux.