Self-amplification of electrons emitted from surfaces in plasmas with E x B fields

• Published in: Plasma sources science & technology Vol. 24; no. 3; pp. 1 - 7
• Main Authors: Campanell, M D, Wang, H, Kaganovich, I D, Khrabrov, A V
• Format: Journal Article
• Language: English
• Published: 01.05.2015
• Subjects: Balancing; Drift; Emittance; Gain; Heating; Plasmas; Transport; Walls
• ISSN: 0963-0252; 1361-6595
• DOI: 10.1088/0963-0252/24/3/034010

Emission from surfaces is known to cause enhanced wall heating and enhanced energy loss from plasma electrons. When E X B fields are present, emitted electrons are heated by the drift motion and cause enhanced transport along E. All emission effects are normally predicted to reach a maximum when the sheath becomes space-charge limited because any 'additional' emitted electrons return to the wall. But the returning electrons are also heated in the E X B drift, further enhancing transport, and return to the wall with extra energy, further enhancing the energy flux. Returning electrons can gain enough energy to induce secondaries, thereby self-amplifying to higher intensities. This newly analyzed mechanism could affect the wall heating, transport and global energy balance under certain conditions. Theory and simulations are presented.