Analysis of Electron and Microwave Behavior in Microwave Discharge Neutralizer

Masui, Hirokazu; Tashiro, Yousuke; Yamamoto, Naoji; Nakashima, Hideharu; Funaki, Ikkoh

doi:10.2322/tjsass.49.87

Cited by 17 publications

(7 citation statements)

References 12 publications

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“…The antenna being closer to the ECR region increases the effective plasma production. 12 Also looking at the electron density distribution of µ20 ion thruster, the electron density can be observed to fall significantly near the walls of the discharge chamber, verifying the sheath formation.…”

Section: Plasma Simulationmentioning

confidence: 80%

Study of the Discharge Chamber Magnetic Field Configuration Effects on the Electron Cyclotron Resonance (ECR) Microwave Ion Thruster

Kamis¹,

Çelik²

2015

51st AIAA/SAE/ASEE Joint Propulsion Conference

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Microwave ion thrusters that employ the gyromotion of the electrons around an external static magnetic field lines to obtain discharge are among the most selected devices for deep space missions that require longer life time. The phenomenon of electron cyclotron resonance (ECR) is utilized to a high degree to energize the electrons in magnetic tubes created by the lines of force and obtain discharge through impact ionization. A discussion for the trade-offs between microwave systems to other electric propulsion systems is presented along with numerical simulations on some designs from literature. COMSOL Multiphysics, a finite element software, is used to conduct magnetic field simulation, electromagnetic simulation and plasma simulation. Results show that the increase in number of magnets and orienting them to form cusps affect the density and temperature distribution by increasing the magnetic tubes in which the electrons are trapped and energized. The R-mode and X-mode resonance regions are plotted, and for 20mN-class ion thruster it is verified that X-mode resonance is the dominant energy transfer mechanism.

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Section: Plasma Simulationmentioning

confidence: 80%

Study of the Discharge Chamber Magnetic Field Configuration Effects on the Electron Cyclotron Resonance (ECR) Microwave Ion Thruster

Kamis¹,

Çelik²

2015

51st AIAA/SAE/ASEE Joint Propulsion Conference

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“…Plasma-microwave coupling deteriorates with an increase in N mag due to the increase in the distance between the antenna and the ECR layer, where the microwave power is absorbed efficiently, 28 as shown in Fig. The maximum thrust achieved is 0.79 mN, at N mag = 12.…”

Section: A Magnetic Field Strengthmentioning

confidence: 99%

Effects of magnetic field configuration on thrust performance in a miniature microwave discharge ion thruster

Yamamoto

Kondo

Chikaoka

et al. 2007

Journal of Applied Physics

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Articles you may be interested inIon ejection from a permanent-magnet mini-helicon thruster Phys. Plasmas 21, 093511 (2014); 10.1063/1.4896238 Measurement of axial neutral density profiles in a microwave discharge ion thruster by laser absorption spectroscopy with optical fiber probes Rev. Sci. Instrum. 82, 123103 (2011); 10.1063/1.3665954 Effect of applied magnetic field on a microwave plasma thruster Phys. Plasmas 15, 023503 (2008); 10.1063/1.2841026 Effect of magnetic field profile on the anode fall in a Hall-effect thruster dischargea) Phys. Plasmas 13, 057104 (2006); 10.1063/1.2174825The ultimate performance of gridded ion thrusters for interstellar missions AIP Conf.The effects of magnetic field configuration on thrust performance in a miniature microwave discharge ion thruster were investigated in order to improve thrust performance. First, the extracted ion beam current was measured for various levels of strength of the magnetic field. It was found that there is an optimum magnitude of the magnetic field. That this is due to the tradeoff between magnetic mirror confinement and microwave-plasma coupling was confirmed by measurement of the ion saturation current into the antenna of the ion thruster. The ion saturation current was found to decrease with an increase in magnetic field strength, due to the improvement in magnetic mirror confinement. The estimated electron temperature also decreases with an increase in magnetic field strength. This result shows that the increase in magnetic field strength leads to a decrease in microwave-plasma coupling. Next, the ion beam current for three magnetic field shapes was measured by changing the length of the central yoke. The results show that the optimum magnetic field shape depends on the mass flow rate because of the tradeoff between magnetic confinement and ionization probability. For the configurations tested, the 3 mm length central yoke is optimal for low mass flow, whereas 7 mm is the best for high mass flow. Overall, the extracted ion beam current is 21.4 mA, at a xenon mass flow rate of 0.036 mg/s, beam voltage of 1500 V, and incident microwave power of 16 W.

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“…As a preceding study of the microwave neutralizer, an electromagnetic PIC analysis was conducted in Kyushu University to investigate the interactions between the microwave and electrons, while ion's motions were not taken into account in the model. 7 In contrast, the Hybrid-PIC model does not include particle's kinetics of electrons, thus the interactions between microwave and electrons were dealt with separately by means of the electromagnetic PIC solver mentioned above. Hereafter, let us refer to this solver as Electron-PIC.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Microwave Neutralizer Including Ion’s Kinetic Effects

Kubota

Watanabe

Yamamoto

et al. 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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In order to analyze a microwave neutralizer in ion's time/space scales, a threedimensional Hybrid-PIC (Particle-In-Cell) solver which treats ions and electrons as particles and fluid was developed. In this analysis, microwave power absorption distribution was estimated by means of another electromagnetic PIC solver. The results show that qualitative agreement on voltage-current characteristics was achieved, whereas a discontinuous current jump between a low current mode and a high current mode was still diffused. It is found that, in the high current mode, the electric potential is gradually increased toward the plume region inside the orifice, which promotes high ion production rate there. It is also shown that the sputtering rate of an antenna is comparable with the measured data, where doublyionized ions mainly produced inside the orifice considerably aggravate the sputtering rate. NomenclatureB = magnetic flux density C = thermal velocity E = electric field e = elementary charge H = magnetic field j = current density k = Boltzmann constant m = mass of particle n = number density P = input power p = pressure 2 q = heat flux T = temperature t = time u = velocity of fluid v = velocity of a particle x = coordinate β = Hall parameter φ = electric potential μ = mobility ν = collision frequency ω p = plasma frequency subscripts abs : absorption anm : anomalous e : electron h : heavy particle (neutral and ion) i : ion s : space (basically represents x = 26 mm) sh : sheath

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Analysis of Electron and Microwave Behavior in Microwave Discharge Neutralizer

Cited by 17 publications

References 12 publications

Study of the Discharge Chamber Magnetic Field Configuration Effects on the Electron Cyclotron Resonance (ECR) Microwave Ion Thruster

Study of the Discharge Chamber Magnetic Field Configuration Effects on the Electron Cyclotron Resonance (ECR) Microwave Ion Thruster

Effects of magnetic field configuration on thrust performance in a miniature microwave discharge ion thruster

Numerical Simulation of Microwave Neutralizer Including Ion’s Kinetic Effects

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