Numerical simulations based on probe measurements in EUV-induced hydrogen plasmaстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 20 мая 2017 г.
Аннотация:We use the two-dimensional particle-in-cell model with Monte Carlo collisions to study the
plasma induced in hydrogen by short pulses of extreme ultraviolet (EUV) radiation at
wavelengths in the range 10–20 nm with a pulse duration of about 40 ns (FWHM). This plasma
is formed via both photoionization by the high-energy EUV photons and by the secondary
photoelectrons emitted from the hydrogen molecules and the irradiated surface. The latter
process can be enhanced by the external electric field that accelerates the electrons. In order to establish a base for our model so as to obtain accurate results, we record a temporally-resolved series of current–voltage characteristics for a small probing electrode inserted into EUV-induced hydrogen plasma. We then resort to simulating this plasma in the same geometry with the probe in our model which we validate by matching its results to the experimentally measured dynamics of the probe current–voltage curves. Having validated the model this way, we use this model as an independent instrument capable of obtaining the spatiotemporal picture of EUV-induced plasma evolution. We use this instrument to study the plasma formation during the EUV pulse and point out the processes that take part in forming this plasma, such as impact ionization and direct ionization by EUV photons.