Direct Vlasov simulations of electron-attracting cylindrical Langmuir probes in flowing plasmas


Autoria(s): Sanchez Arriaga, Gonzalo; Pastor-moreno, D.
Data(s)

2014

Resumo

Current collection by positively polarized cylindrical Langmuir probes immersed in flowing plasmas is analyzed using a non-stationary direct Vlasov-Poisson code. A detailed description of plasma density spatial structure as a function of the probe-to-plasma relative velocity U is presented. Within the considered parametric domain, the well-known electron density maximum close to the probe is weakly affected by U. However, in the probe wake side, the electron density minimum becomes deeper as U increases and a rarified plasma region appears. Sheath radius is larger at the wake than at the front side. Electron and ion distribution functions show specific features that are the signature of probe motion. In particular, the ion distribution function at the probe front side exhibits a filament with positive radial velocity. It corresponds to a population of rammed ions that were reflected by the electric field close to the positively biased probe. Numerical simulations reveal that two populations of trapped electrons exist: one orbiting around the probe and the other with trajectories confined at the probe front side. The latter helps to neutralize the reflected ions, thus explaining a paradox in past probe theory.

Formato

application/pdf

Identificador

http://oa.upm.es/35435/

Idioma(s)

eng

Publicador

E.T.S.I. Aeronáuticos (UPM)

Relação

http://oa.upm.es/35435/1/INVE_MEM_2014_191759.pdf

http://scitation.aip.org/content/aip/journal/pop/21/7/10.1063/1.4889732

info:eu-repo/grantAgreement/EC/FP7/262972

info:eu-repo/semantics/altIdentifier/doi/10.1063/1.4889732

Direitos

http://creativecommons.org/licenses/by-nc-nd/3.0/es/

info:eu-repo/semantics/openAccess

Fonte

Physics of Plasmas, ISSN 1070-664X, 2014, Vol. 21

Palavras-Chave #Física
Tipo

info:eu-repo/semantics/article

Artículo

PeerReviewed