No abstract

A collisional magnetized plasma consisting of two temperature electrons has been investigated numerically to study the sheath structure and the ion energy flux to the wall. The low-temperature electrons are described by Maxwellian distribution, and the high-temperature electrons are described by truncated Maxwellian distribution. It has been observed that high-temperature electrons play a major role in the sheath potential as well as the ion energy flux to the wall. The presence of collision in the sheath has a significant effect on the properties of the sheath.The study of such a system can help in understanding of plasma surface interaction.

A criterion of sheath formation is obtained for magnetized low pressure plasmas. The criterion includes the effect of both collision and the magnetic field. The collision parameter is defined by the ratio of the ionization length to the ion mean free path. The ionization frequency is assumed to be constant. The condition obtained is consistent with the electrostatic case. In the absence of the magnetic field and the collision, it retrieves the Bohm criterion at the sheath edge. For an electrostatic case in the absence of ion neutral collision, the Bohm criterion determines the ion entry speed within the sheath. However, the presence of collision limits the validity of the criterion to a threshold value of the collision parameter. In the magnetized scenario, the validity is found to be dependent on the magnetic field angle besides the collision parameter. Even in a collisionless scenario, the validity is in question depending on the field angle. A critical collision parameter is found for a definite magnetic field strength beyond which there is no more angle dependency on the validity criterion. The effect of the magnetic field on the space charge deposition is highlighted.

In this paper, the central concern is to analyze the influence of the forces that controls the ion dynamics inside a magnetized plasma sheath under collisionless conditions. The ionization effects are considered within the sheath. The magnetic field is tilted in x-z plane and makes an angle with the x-axis. The motivation of the paper is to see the effect of both field strength variation and the variation of the inclination angle on the force fields inside the sheath. The pitch length and pitch angle for the particle velocity field is also calculated and has been found to vary widely with the inclination angle and the strength of the magnetic field. The role of the Lorentz force and energy acquired by the ions while moving towards the wall is highlighted. A comparison between two different ion sources has also been foregrounded.

The role of hot electrons in the charging of dust grains is investigated in a two-temperature hydrogen plasma. A variety of dust particles are introduced into the system and secondary electron emission (SEE) from each of the dust grains has been reported. A cylindrical Langmuir probe is used for determining the plasma parameters and a Faraday cup is connected to an electrometer in order to measure the dust current. The electrometer readings confirm the electron emission from the dust and SEE is observed from the tungsten dust in a low-pressure experimental plasma device for the first time.