Kinetic sheath in presence of multiple positive ions, negative ions, and particle wall emission

Schiesko, L.; Wünderlich, D.; Montellano, I. M.

doi:10.1063/1.5132596

Cited by 7 publications

(7 citation statements)

References 56 publications

(90 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For Φ well ∼ −1.3 V, the saturation current is on the order of 6.8 A.m −2 , close to the calculated value (6 A.m −2 ). The threshold for the appearance of the saturated regime has been recently derived analytically and extended to the case of multiple charge species in the work of Schiesko et al 143 . By applying −5 V at the LB plane, negative ions move back and forth trapped by the electric potential before being destroyed by detachment processes or extracted.…”

Section: Extraction Of Negative Ionsmentioning

confidence: 99%

Tutorial: Modeling of the extraction and acceleration of negative ions from plasma sources using particle-based methods

Garrigues

Fubiani

2023

Journal of Applied Physics

View full text Add to dashboard Cite

In this Tutorial, we consider plasma sources with applications to fusion devices and high energy accelerators. These ion sources typically produce negative ions from hydrogen-isotope gases, which are extracted through one or multiple apertures and accelerated to high kinetic energies. Next, they are either double stripped of two electrons to form positive ions used as precursors in accelerator devices or neutralized to produce a neutral beam injected in tokamak reactors. Contrary to the working conditions of most ion sources where volume production prevails, the mechanism of negative ion production by dissociative electron attachment on vibrationally excited molecules inside the plasma volume of fusion-type hydrogen-fueled high power discharges is mostly balanced by their destruction by detachment before being extracted rendering this means of producing negative ions rather inefficient. Surface production through the transfer of electrons from low work function metallic materials to the impacting atoms is the alternative solution to fulfill the requirements for the applications concerned. Negative ions are produced close to the aperture from which they are extracted. As a result, the analysis and understanding of the extraction mechanisms through experimental diagnostics is rather difficult due to the lack of accessibility and can only give a partial view. In addition, most of the experimental work is focused on the validation of requirements for the applications and not to the investigation of the fundamental processes that take place inside these types of sources. This Tutorial is focused on the description and understanding of the physical mechanisms behind the extraction and acceleration of negative ions from hydrogen plasma sources through modeling methods. We describe the numerical techniques of particle-based methods with a specific emphasis on particle-in-cell Monte Carlo collision algorithms. An analysis of the physical processes involved in driving the negative ions from the plasma source, across the apertures and inside the accelerator as reported in the literature, is presented in detail. This Tutorial concludes with additional and future works to be addressed in the coming years.

show abstract

Section: Extraction Of Negative Ionsmentioning

confidence: 99%

Tutorial: Modeling of the extraction and acceleration of negative ions from plasma sources using particle-based methods

Garrigues

Fubiani

2023

Journal of Applied Physics

View full text Add to dashboard Cite

show abstract

“…The intricacies of sheaths have made them one of the most researched topics in plasma physics. Although they have been studied and understood by both fluid [1][2][3][4][5][6][7] and kinetic approaches [8][9][10][11][12], there is enough scope to investigate the problem further. In the case of the fluid approach, usually, the ions are governed by the hydrodynamic equations and the distribution of electrons are defined by Maxwell-Boltzmann statistics.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, the Boltzmann behaviour restricts the electron distribution to the macroscopic ergodic equilibrium state and is often found to be inadequate to describe long-range interactions [20]. Also, the plasma sheath is regarded as a transition region between the plasma and the wall and is considered a non-neutral region besides possessing a non-Maxwellian nature [12,21]. Due to such characteristics, the sheath plays a substantial role in influencing the particle and energy transport towards the wall.…”

Section: Introductionmentioning

confidence: 99%

Study of a collisionless magnetized plasma sheath with nonextensively distributed species

Paul

Deka

Sharma

et al. 2023

Plasma Sci. Technol.

View full text Add to dashboard Cite

A weakly magnetized sheath for a collisionless, electronegative plasma comprisedof positive ions, electrons, and negative ions is investigated numerically using thefluid approach. The electrons are considered to be non-Maxwellian in nature andare described by Tsalli’s distribution. Such electrons have a substantial effect on thesheath properties. The study also reveals that non-Maxwellian distribution is themost realistic description for negative ions in the presence of an oblique magnetic field.In addition to the negative ion temperature, the sheath potential is also affected bythe non-extensive parameters. The present research finds application in the plasmaprocessing and semiconductor industry as well as in space plasmas.

show abstract

“…Although the magnetic filter field is helpful for increasing the extraction probability of negative ions [14] and decreasing the electron temperature, the negative ion density is almost unchanged because of the decreased electron density [15]. Furthermore, a higher value of plasma density near the plasma grid is helpful for the surface production [15][16][17]. Hence, it is of significant importance to control the magnetic field topology to increase the plasma density.…”

Section: Introductionmentioning

confidence: 99%

Influence of magnetic filter field on the radio-frequency negative hydrogen ion source of neutral beam injector for China Fusion Engineering Test Reactor

Wang¹,

Huang²,

Zhang³

et al. 2021

Plasma Sci. Technol.

View full text Add to dashboard Cite

In the design of negative hydrogen ion sources, a magnetic filter field of tens of Gauss at the expansion region is essential to reduce the electron temperature, which usually results in a magnetic field of around 10 Gauss in the driver region, destabilizing the discharge. The magnetic shield technique is proposed in this work to reduce the magnetic field in the driver region and improve the discharge characteristics. In this paper, a three-dimensional fluid model is developed within COMSOL to study the influence of the magnetic shield on the generation and transport of plasmas in the negative hydrogen ion source. It is found that when the magnetic shield material is applied at the interface of the expansion region and the driver region, the electron density can be effectively increased. For instance, the maximum of the electron density is 6.7 10 17 m −3 in the case without the magnetic shield, and the value increases to 9.4 10 17 m −3 when the magnetic shield is introduced.

show abstract

Kinetic sheath in presence of multiple positive ions, negative ions, and particle wall emission

Cited by 7 publications

References 56 publications

Tutorial: Modeling of the extraction and acceleration of negative ions from plasma sources using particle-based methods

Tutorial: Modeling of the extraction and acceleration of negative ions from plasma sources using particle-based methods

Study of a collisionless magnetized plasma sheath with nonextensively distributed species

Influence of magnetic filter field on the radio-frequency negative hydrogen ion source of neutral beam injector for China Fusion Engineering Test Reactor

Contact Info

Product

Resources

About