Novel Control of Magnetoplasma Thruster by Using a Rotating Radio Frequency System

Yasaka, Y.; Nishino, Seiji; Yamamoto, Masakazu; Nakamoto, S.

doi:10.2514/1.b34271

Cited by 5 publications

(2 citation statements)

References 18 publications

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“…In these applications, hydrogen atoms are the main active species interacting with the surface, and a high degree of dissociation is required; this parameter is considered as one of the most important parameters of hydrogen containing plasmas. Another characteristic of hydrogen discharges is the generation of highly negative ion sources for a variety of applications such as ion beam deposition, plasma space propulsion [10,11] or intense beams of energetic neutrals for fusion plasma heating [12]. The two latter applications need to operate at much lower pressure in the pressure range 0.3-1 Pa.…”

Section: Introductionmentioning

confidence: 99%

Chemical kinetics of low pressure high density hydrogen plasmas: application to negative ion sources for ITER

Boeuf

2014

Plasma Sources Sci. Technol.

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This paper presents a systematic kinetic characterization of a low pressure high power hydrogen plasma. The plasma physics is described with a global model coupled to a homogeneous kinetic model for hydrogen. This model involves reactions which describe the vibrational and electronic excited kinetics of H 2 , the positive H + ,H + 2 ,H + 3 and negative (H − ) ion kinetics and the H chemistry. This enables the estimation of the particle density and the electron temperature and their evolutions as a function of power (1-100 kW) and pressure (0.3-4 Pa). These very specific plasma conditions involve physical phenomena not occurring in more usual plasmas, such as gas depletion. To account for this gas depletion, we incorporate in the global model both the H neutral heat equation to calculate the H temperature, and the gas pumping. Indeed, the gas depletion is mainly due to H atom heating leading to a higher pumping loss for H atoms. The consideration of the gas depletion allows us to obtain similar behaviors to the experiments when varying power and pressure. From an accurate analysis of the main formation and destruction pathways for each particle, the species kinetics is discussed and a simplified kinetic model that may be used to describe the non-equilibrium plasma in the negative source for ITER is proposed. Finally, the results point to strong coupling existing between the H atom wall recombination coefficient γ H and the gas depletion. An increase of γ H reduces the gas depletion, affecting the electron temperature and the electron density as well as the whole plasma kinetics.

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Section: Introductionmentioning

confidence: 99%

Chemical kinetics of low pressure high density hydrogen plasmas: application to negative ion sources for ITER

Boeuf

2014

Plasma Sources Sci. Technol.

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“…The configuration of the experimental apparatus [12] is the same as shown in Figure 2 with the loop antenna replaced by the helical antenna of right helical pitch in the +z direction that is shown in Figure 1. The ion saturation current I is corresponding to the plasma density is measured by a Langmuir probe (LP) located at z = −320 mm and the parallel ion temperature T i by a Faraday cup (FC) at z = 260 mm (see Figure 2).…”

Section: Apparatusmentioning

confidence: 99%

Bi-Directional Excitation of Radio Frequency Waves Using a Helical Antenna in Non-Uniform Plasmas towards a Compact Magnetoplasma Thruster

Yasaka¹,

Hayashi²,

Takeno³

et al. 2014

OJAppS

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Magnetoplasma thruster is one of the attractive plasma engines for space propulsion in future manned deep space exploration. Usually two helical antennas are equipped to produce and heat plasmas with separate radio frequency sources. It is presented in this paper that a helical antenna, which is used to launch one wave mode in one direction so far, exhibits bi-directional nature, where the waves with different mode numbers are launched and couple with electrons and ions selectively in opposite directions. A two-dimensional numerical calculation is performed to predict wave propagation and power absorption in a non-uniform hydrogen plasma immersed in a non-uniform external static magnetic field, based on the hot plasma theory. It is confirmed that appropriate choice of the excitation condition of the antenna can select axial propagation direction of specific wave modes and consequently select a species that absorbs power from generated waves. A small-scale experiment is performed to confirm the prediction of the calculation. By measuring a change in electron and ion temperatures due to the wave launch from the helical antenna, it is found that both the production and heating at different axial positions are accomplished simultaneously by one antenna showing that another type of the radio frequency driven magnetoplasma thruster would be achieved.

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Investigation of the power transfer efficiency in a radio-frequency driven negative hydrogen ion source

Gao

Wen

et al. 2019

Journal of Applied Physics

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The radio frequency power transfer efficiency is experimentally and numerically investigated in an inductively coupled negative hydrogen ion source. The discharge is operated in a low pressure range of 0.1–3 Pa at a driving frequency of 2 MHz and an applied power of up to 6 kW. In the experiment, the power transfer efficiency value is determined by measuring the applied power and current through the antenna coil both with and without discharge operation. Fundamental properties, such as electron density and effective electron temperature, are obtained by means of a Langmuir probe. The effect of the antenna coil turns, N, is also studied in a range of 5–9 turns. It is found that more coil turns can significantly enhance the power transfer efficiency due to the remarkably increasing quality factor of the system. Moreover, the experimental results show that the power transfer efficiency first increases and then reaches the maximum with increasing applied power, while it first increases quickly and then rises at a slower rate with increasing gas pressure. In order to give a comprehensive knowledge of the power absorption mechanism, a self-consistent hybrid model is developed. It is found that the numerical results are in reasonable agreement with that measured in the experiment. The numerical results and the analytic solutions in the limit cases of low and high pressures can well explain the various trends of the power transfer efficiency obtained in the experiment. These trends mainly depend on the quality factor Q, the electron density, and the effective electron collision frequency.

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Novel Control of Magnetoplasma Thruster by Using a Rotating Radio Frequency System

Cited by 5 publications

References 18 publications

Chemical kinetics of low pressure high density hydrogen plasmas: application to negative ion sources for ITER

Chemical kinetics of low pressure high density hydrogen plasmas: application to negative ion sources for ITER

Bi-Directional Excitation of Radio Frequency Waves Using a Helical Antenna in Non-Uniform Plasmas towards a Compact Magnetoplasma Thruster

Investigation of the power transfer efficiency in a radio-frequency driven negative hydrogen ion source

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