Bulletin of the American Physical Society
75th Annual Gaseous Electronics Conference
Volume 67, Number 9
Monday–Friday, October 3–7, 2022;
Sendai International Center, Sendai, Japan
The session times in this program are intended for Japan Standard Time zone in Tokyo, Japan (GMT+9)
Session GR1: Plasma Propulsion I |
Hide Abstracts |
Chair: Kazuma Emoto, Yokohama National University Room: Sendai International Center Shirakashi 2 |
Thursday, October 6, 2022 8:00AM - 8:15AM |
GR1.00001: Plasma Creation and Evaluation of Flight Performance on Multi-parabola Laser Thruster Propelled by Repetitive Pulses Yuya Hayadate, Masayuki Takahashi, Koichi Mori Laser propulsion systems are attracting attention as a new launch method in space development. An intense laser is irradiated onto the vehicle from the ground and focused by a mirror to ignite a plasma. The plasma then absorbs an energy of the succeeding laser, generating blast waves that propel the vehicle. In this system, the vehicle must have the ability to fly while following the axis of the incident beam. Myrabo successfully launched the lightcraft-type vehicle to an altitude of 71 m in a free-flight experiment. However, the vehicle has a tendency to tilt with respect to the laser axis, and in fact, in that experiment, the vehicle was rotated at 10,000 rpm to obtain a gyroscopic effect, which is far from being practical. The multi-parabola thruster has been proposed by Kogushi et al. as a vehicle with better flight performance than the lightcraft. In this study, we conducted breakdown experiments of the multi-parabola thruster using repetitive pulses laser to observe an ignition process of the dense plasma and to evaluate its flight performance. Camera imaging revealed that the plasma was successfully created when the laser beam was focused by the parabolic mirror, which repeatedly supplied propulsive forces to the vehicle and contributed to an increase in flight altitude. |
Thursday, October 6, 2022 8:15AM - 8:30AM |
GR1.00002: Effect of Flow Velocity on Generation Conditions of Argon LSP using Diode Laser Seiichiro Takano, Kota Okamoto, Yamato Homme, Makoto Matsui Laser propulsion is a novel space transportation system that obtains thrust through the laser sustained plasma (LSP) generated by the focused laser beam. This system is expected to have a higher specific impulse than arcjet system and long lifetime because of no electrode erosion. Considering the adaption of LSP to the space transportation system, it is necessary to generate LSP using a diode laser which has high energy conversion efficiency. In previous studies, we have successfully generated diode laser sustained plasma under conditions of argon gas inclusion. However, in consideration of the application to laser propulsion, it is necessary to investigate the generation condition of LSP and various characteristics under flow velocity conditions. In this study, we investigated changes in the generation conditions depending on the flow velocity. |
Thursday, October 6, 2022 8:30AM - 8:45AM |
GR1.00003: Electron properties comparison of microwave cathode and hollow cathode by incoherent laser Thomson scattering Takuya Koiso, Yusuke Yamashita, Ryudo Tsukizaki, Kazutaka Nishiyama We report a measurement of electron properties at the plume region of a microwave cathode and a hollow cathode by incoherent laser Thomson scattering (incoherent LTS). Compared to probe measurements, incoherent LTS can directly measure electron velocity distribution function(EVDF) with less disturbance. In addition, it is suitable to measure non-Maxwellian EVDF. However, measuring plasma around electric propulsion systems is generally difficult, whose typical electron density is 10^16~10^18 m^-3 and whose typical electron temperature is 1-10eV. In this work, to realize the measurement, laser stray light noise is drastically reduced using a triple monochromator with a notch slit. Then, to improve the signal-to-noise ratio (S/N), a photon-counting technique is applied. We succeed in measuring the electron number density of 10^17 m^-3 ~10^18 m^-3 at the plume region of microwave cathode and Hollow cathode. The results provide the difference in electron properties such as electron temperature and bulk velocity between these cathodes. |
Thursday, October 6, 2022 8:45AM - 9:00AM |
GR1.00004: Beam Focusing Performance of Microwave-Driven In-Tube Accelerator Toshiki Yamada, Masayuki Takahashi, Kohei Shimamura Numerical simulation and experiment of a microwave beaming propulsion system, microwave-driven in-tube accelerator (MITA), was conducted. In MITA system, the vehicle is placed in the waveguide, and the microwave beam is irradiated into the front side of the vehicle. The beam is reflected by the front mirror of the vehicle and the waveguide and then focused at the vehicle's rear side. The focused beam causes breakdown of the atmosphere, and the generated plasma induces the shock wave through a gas heating process. In the numerical simulation, 28 GHz microwave beam was irradiated into the two-dimensional axisymmetric model of MITA to investigate microwave propagation and thrust performance. It showed a better performance at beam focusing and thrust generation, when larger size of waveguide and vehicle was used. In the experiment, 28 GHz low-power microwave beam was irradiated into the MITA model to investigate the beam focusing process of MITA. Microwave beam was successfully focused at the rear side of the vehicle, and it showed a large power density at the focal point. The larger size model showed a better beam focusing performance. |
Thursday, October 6, 2022 9:00AM - 9:15AM |
GR1.00005: Investigation of Generating Conditions of Fiber Laser-Sustained Plasma using Argon Kota Okamoto, Seiichiro Takano, Yamato Homme, Makoto Matsui Laser sustained plasma (LSP) is a heat source for laser propulsion. A diode laser is suitable for a laser thruster because the energy conversion efficiency is high and the lifetime is long. In a previous study, the LSPs were successfully generated using argon gas. However, because the intensity of the laser beam cannot be increased due to the problem of the focusing performance, the pressure and the laser power required to generate the LSPs become high. In this study, we investigate the conditions of generating the LSPs using a fiber laser that the focusing performance is superior. |
Thursday, October 6, 2022 9:15AM - 9:30AM |
GR1.00006: Numerical modeling and evaluation of 8.2-GHz microwave electrothermal thruster (MET) performance using atomic and molecular gases Juyeon Lee, Laxminarayan L Raja Microwave Electrothermal Thrusters (MET) have been proposed as a feasible electric propulsion (EP) system for micro- and nano satellites with an intermediate thrust and specific impulse range. The MET use microwave energy to heat propellant gas and sustain a plasma through collisions between free electrons and heavy particles within electromagnetic resonant cavity. This study was motivated by the need for a computational modeling that encompasses complex multi-physics of electromagnetics, fluid dynamics and plasma phenomena. We develop a 2D axisymmetric model of 8.2-GHz resonant cavity consisting of an empty and plasma section divided by a dielectric plate, and a nozzle at the end of the plasma section. In this study, we first find a resonant frequency in the absence of plasma (unloaded cavity) and implement cold gas flow without microwave power. Then we demonstrate the highly coupled effect of wave-flow-plasma phenomena in the MET discharge using helium and ammonia gases as propellants. To evaluate the MET performance, we calculate thrust and specific impulse using simulation data and perform several parametric studies. From our preliminary results, we observed that the specific impulse is dependent on the microwave input power, on the other hand, the thrust is sensitive to the mass flow rate. In our final work, comprehensive parametric studies to optimize the performance of MET will be included. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700