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The spatio-temporal development of electron swarms in gases: moment equation analysis and Hermite polynomial expansion
Title: | The spatio-temporal development of electron swarms in gases: moment equation analysis and Hermite polynomial expansion |
Authors: | Sugawara, Hirotake Browse this author →KAKEN DB | Sakai, Y. Browse this author | Tagashira, H. Browse this author | Kitamori, K. Browse this author |
Issue Date: | Feb-1998 |
Publisher: | Institute of Physics |
Journal Title: | Journal of Physics D: Applied Physics |
Volume: | 31 |
Issue: | 3 |
Start Page: | 319 |
End Page: | 327 |
Publisher DOI: | 10.1088/0022-3727/31/3/011 |
Abstract: | Spatio-temporal development of electron swarms in gases is simulated using a propagator method based on a series of one-dimensional spatial moment equations. When the moments up to a suecient order are calculated, the spatial distribution function of electrons, p(x), can be constructed by an expansion technique using Hermite polynomials and the weights of the Hermite components are represented in terms of the electron diausion coeecients. It is found that the higher order Hermite components tend to zero with time, that is, the normalized form of p(x) tends to a Gaussian distribution. A time constant of the relaxation is obtained as the ratio of the second- and third-order diausion coeecients, D2 3=D3L . The validity of an empirical approximation in time-of-cight experiments that treats p(x) as a Gaussian distribution is indicated theoretically. It is also found that the diausion coeecient is deaned as the derivative of a quantity called the cumulant which quantiaes the degree of deviation of a statistical distribution from a Gaussian distribution. |
Rights: | Copyright © 1998 Institute of Physics |
Relation: | http://www.iop.org/EJ/journal/JPhysD |
Type: | article (author version) |
URI: | http://hdl.handle.net/2115/11393 |
Appears in Collections: | 情報科学院・情報科学研究院 (Graduate School of Information Science and Technology / Faculty of Information Science and Technology) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 菅原 広剛
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