The retrograde motion of arc cathode spots in vacuum

摘要: Experiments are reported on the retrograde arc spot motion copper and tantalum cathodes in vacuum presence of a magnetic field. The spots imaged with time space resolutions <100?ns <10??m, respectively. flux density amounted to B = 0.4?T currents 2-100?A. For times <1??s random displacement occurs scale <100?ns. At intervals about 4??s, jumps observed over distances 50-300??m direction, thus yielding macroscopic velocities 50?m?s-1. preceded by ejection plasma jets having average v 5?km?s-1. New formed exactly jet direction. explained instabilities magnetically confined plasma, formation electric fields ? within jets. ejected periods enhanced production caused inner processes, i.e., dynamics fragments cells, diameters ?20 ?10??m, No reversal has been at elevated temperatures up 2100?K.