2D limiting current of a finite-width electron pulse in a parallel-plate gap

摘要: The generation of pC-nC electron pulses is an important technique to produce a high-energy electron beam in applications, such as photoinjectors and laser wakefield accelerators. For an electron pulse with a large charge number, the space-charge effect is probably the main factor limiting the maximum charge number that can be packed in a pulse. The 1D space-charge-limited (SCL) current for a short pulse emitted from a planar cathode was first proposed in 2002 [1]. This 1D SCL model is later extended to the quantum, relativistic [2] and multi-dimensional (2D/3D)[3] regimes. In previous models [1-3], uniform electron beam is assumed, but in reality, the injected current of the short pulse is usually non-uniform. Therefore, we present the 2D non-uniform short-pulse model and compare the numerical results with the uniform injection model in Ref.[3].[1]'A. Valfells, et. al., Phys. Plasmas 9, 2377 (2002).[2] LK Ang, et …