An Efficient Vlasov-Poisson Solver and Deep Parametric Analysis of Cylindrical Emissive Probes*

The Orbital Motion Theory (OMT) for cylindrical emissive probes immersed in collisionless plasmas, which uses conservation laws to write the Vlasov-Poisson system as a single integro-differential equation, has been developed recently and solved numerically for specific parameter values. This work presents an improvement in the code that reduces the computational cost by a factor of approximately 80, thus opening the opportunity to carry out deep parametric analysis. By varying the probe radius-to-Debye length ratio and the emission level (controlled by the probe temperature), a database of current-voltage characteristics has been computed. The transition boundaries in parameter space from Orbital-Motion-Limited (OML) to non-OML regimes and from space-charge-limited (SCL) to non-SCL regimes have been found. The analysis shows that, depending on the emission level, the probe can float at positive and negative biases, with the floating potential not~ saturated at high emission levels.~~