Time evolution of the electron energy distribution function in pulsed microwave magnetoplasma in H2

Abstract

International audienceTime evolution of the Electron Energy Distribution Function(EEDF) is measured in pulsed hydrogen microwave magnetoplasma working at 2.45 GHz. Analysis is performed both in resonance (B = 0.087 T) and off-resonance conditions (B = 0.120 T), at two pressures (0.38 Pa and 0.62 Pa), respectively, and for different incident microwave powers. The important effect of the magnetic field on the electron kinetic is discussed, and a critical analysis of Langmuir probe measurements is given. The Electron Energy Distribution Function is calculated using the Druyvesteyn theory (EEDF) and is corrected using the theory developed by Arslanbekov in the case of magnetized plasma. Three different components are observed in the EEDF, whatever the theory used. They are: (a) a low electron energy component at energy lower than 10 eV, which is ascribed to the electron having inelastic collisions with heavy species (H2, H, ions), (b) a high energy component with a mean energy ranging from 10 to 20 eV, which is generally ascribed to the heating of the plasma by the incident microwave power, and (c) a third component observed between the two other ones, mainly at low pressure and in resonance conditions, has been correlated to the electron rotation in the magnetic field

Electron cyclotron resonance ion source plasma characterization by energy dispersive x-ray imaging

“…Any significant step forward in ECRIS physics and technology requires diagnostics tools of various types. Therefore, since the development of the first ECR ion sources, different plasma diagnostics methods were developed and adapted: microwave interferometry [5], x-ray spectroscopy [6,7] (including precise energy and spatial resolution), visible light observations [8], and small-size electrostatic (Langmuir) probes [9,10].…”

Time resolved measurements of hydrogen ion energy distributions in a pulsed 2.45 GHz microwave plasma

“…2 This diagnostic technique could give valuable information when used on a 2.45 GHz Electron Cyclotron Resonance (ECR) plasma typically applied for high-current light ion sources. In such devices, the role of electrons as responsible for the energy coupling between the plasma and RF or microwaves [3][4][5] is especially critical and well-studied. However, the dynamics of energy transfer processes between electrons and ions by the Coulomb interaction and especially by inelastic collisions, e.g., molecular dissociation and ionization, is less understood.…”

Lost electron energy distribution of electron cyclotron resonance ion sources

“…One of the simplest methods is Langmuir probe diagnostics and subsequent analysis of the I-V characteristics within the frame of Druyvesteyn theory. 28 However, even the modified Arslanbekov's theory, being successful for measuring the EED in low-temperature microwave-heated plasmas 29 of singly charged ions, is inapplicable for ECRIS of multicharged ions. This is due to the invasive nature of the probe, which in the case of rarefied ECRIS plasma perturbs the equilibrium and distorts the EED both locally and globally.…”