真空中连续发射电子束形成的电子鞘层的空间结构

用双流理论模型研究真空中电子束的发射实验。向真空中发射电子束过程中,发射体本身被充正电,束缚束电子向外传播,大量的束电子在发射体表面附近形成电子鞘层;只有极少量的束电子可以逃离发射体而向外传播出去。在电子鞘层内,发射出的束电子和返回发射体表面的束电子形成速度和密度在空间为分布不均匀的双流。本文用双流理论模型解析计算出了电子鞘层的空间尺度、电子鞘层内的电场分布以及电子密度分布。 

THE SHEATH STRUCTURE FORMED BY ELECTRON BEAM CONTINUOUS INJECTION INTO VACUUM

Aone-dimensional, two-stream analytical code has been developed to study the sheath structure formed by electron beam continuously injected into vacuum. Injected electrons will be decelerated and then drawn back to the surface of the spacecraft by the positive charges due to the electron beam injection into the vacuum from the spacecraft. The injection beam and return beam form two electron streams with the same density and velocity distribution in the sheath. The stagnetion point is at x=v_o/(3ω_o)(where v_o is the initial velocity of beam injection, ω_o is the plasmafrequancy of incipient injected electrons). Also, electric field distribution and electron density distribution in the sheath are given out in this paper.