TY - JOUR

T1 - Kinetic theory of the cathode sheath in low-voltage beam discharges

AU - Сухомлинов, Владимир Сергеевич

AU - Мустафаев, Александр

AU - Badr, Abdul

AU - Тимофеев, Николай Александрович

PY - 2025/11/1

Y1 - 2025/11/1

N2 - The work is devoted to the development of the kinetic theory of the cathode sheath of a low-voltage beam discharge in rare gases at Knudsen numbers of the order of 1. It is under these conditions that this plasma system is promising for creating plasma electronics devices. It is found that the structure of the cathode sheath of such a discharge is fundamentally different from that of a self-sustained glow discharge. In particular, the spatial dependence of the electric field may not be monotonic and may contain a maximum. At the same time, the values of the electric field near the cathode turn out to be significantly lower, the spatial dependences of the electron and ion densities may have a minimum, and the lengths of the quasi–neutral pre-sheath and the cathode part of the perturbed sheath, where quasi-neutrality is significantly disrupted, increase significantly. The reason for these changes is the presence of a beam of electrons emitted by the heated cathode and accelerated from the cathode to the plasma, and electrons with energy of the order of the ionization potential of the plasma–forming gas, which have experienced elastic collisions with atoms and have an isotropic distribution in the directions of motion. It has been found that a decrease in the electric field near the cathode leads to the fact that the average energy of ions bombarding the cathode is several times less than for the same conditions in a glow discharge without an electron beam. The results obtained make it possible to proceed to the development of a kinetic theory of three-electrode plasma systems based on a low-voltage beam discharge.

AB - The work is devoted to the development of the kinetic theory of the cathode sheath of a low-voltage beam discharge in rare gases at Knudsen numbers of the order of 1. It is under these conditions that this plasma system is promising for creating plasma electronics devices. It is found that the structure of the cathode sheath of such a discharge is fundamentally different from that of a self-sustained glow discharge. In particular, the spatial dependence of the electric field may not be monotonic and may contain a maximum. At the same time, the values of the electric field near the cathode turn out to be significantly lower, the spatial dependences of the electron and ion densities may have a minimum, and the lengths of the quasi–neutral pre-sheath and the cathode part of the perturbed sheath, where quasi-neutrality is significantly disrupted, increase significantly. The reason for these changes is the presence of a beam of electrons emitted by the heated cathode and accelerated from the cathode to the plasma, and electrons with energy of the order of the ionization potential of the plasma–forming gas, which have experienced elastic collisions with atoms and have an isotropic distribution in the directions of motion. It has been found that a decrease in the electric field near the cathode leads to the fact that the average energy of ions bombarding the cathode is several times less than for the same conditions in a glow discharge without an electron beam. The results obtained make it possible to proceed to the development of a kinetic theory of three-electrode plasma systems based on a low-voltage beam discharge.

UR - https://www.mendeley.com/catalogue/dca50446-8b3b-3969-93a2-f4161f645a2a/

U2 - 10.1063/5.0290540

DO - 10.1063/5.0290540

M3 - Article

VL - 32

JO - Physics of Plasmas

JF - Physics of Plasmas

SN - 1070-664X

IS - 11

M1 - 113501

ER -