Thrust Characteristics of High-Density Helicon Plasma Using Argon and Xenon Gases
01 Mar 2017-Journal of Propulsion and Power (American Institute of Aeronautics and Astronautics)-Vol. 33, Iss: 2, pp 420-424
TL;DR: In this article, the authors proposed a helicon plasma thruster to develop a completely electrodeless electric thruster using high-density helicon plasmas, which involves two processes: the generation of source dense plasma by using a helicon wave, and the additional acceleration of the generated plasma by generating the Lorentz force generated by the product of the induced azimuthal current and external radial magnetic field.
Abstract: A helicon plasma thruster has been studied to develop a completely electrodeless electric thruster using high-density helicon plasmas. The proposed helicon plasma thruster involves two processes: the generation of source dense plasma by using a helicon wave, and the additional acceleration of the generated plasma by using the Lorentz force generated by the product of the induced azimuthal current and external radial magnetic field. This additional acceleration method requires additional electrodes or coils, leading to a longer discharge tube. Therefore, it is necessary to find a good configuration that minimizes wall losses within the discharge tube. Here, thrust characteristics such as thrust, thrust-to-power ratio, specific impulse, and thrust efficiencies of argon and xenon gases were studied, using a radio frequency of 7 MHz and an input power less than 3 kW, to optimize the target plasma without employing an additional acceleration method. A helicon plasma source, with electromagnets and permanent ma...
Citations
More filters
01 Dec 2019
TL;DR: In this paper, the authors reviewed the fundamental physics relating to the thruster development and the technology for the compact and efficient system, and the current status of the thrusters performance.
Abstract: Development of electrodeless radiofrequency plasma thrusters, e.g., a helicon thruster, has been one the of challenging topics for future high-power and long-lived electric propulsion systems. The concept simply has a radiofrequency plasma production/heating source and a magnetic nozzle, while it seems to include many aspects of physics and engineering issues. The plasma produced inside the source is transported along the magnetic field lines and expands in the magnetic nozzle, where the plasma is spontaneously accelerated into the axial direction along the magnetic nozzle, yielding a generation of the thrust force. Hence, the plasma transport and spontaneous acceleration phenomena in the magnetic nozzle are key issues to improve the performance of the thrusters. Since the thrust is equal in magnitude and opposite in direction to momentum flux exhausted from the system, the direct measurement of the thrust can reveal not only the thruster performance but also fundamental physical quantity of plasma momentum flux. Here studies on fundamental physics relating to the thruster development and the technology for the compact and efficient system are reviewed; the current status of the thruster performance is shown. Finally, a recently proposed future new application of the thruster is also discussed.
133 citations
18 Jan 2018
TL;DR: In this paper, high-density (up to ~1013 cm−3) plasma sources using a radio frequency wave in the presence of a magnetic field under a low pressure are very promising for various application fields owing to their high density.
Abstract: Helicon high-density (up to ~1013 cm−3) plasma sources using a radio frequency wave in the presence of a magnetic field under a low pressure are very promising for various application fields owing ...
68 citations
TL;DR: In this article, two dimensional profiles of electron temperature are measured inside and downstream of a radiofrequency plasma thruster source having a magnetic nozzle and being immersed in vacuum, and the results show that the peripheral high temperature electrons in the magnetic nozzle originate from the upstream antenna location and are transported along the connecting magnetic field lines.
Abstract: Two dimensional profiles of electron temperature are measured inside and downstream of a radiofrequency plasma thruster source having a magnetic nozzle and being immersed in vacuum. The temperature is estimated from the slope of the fully swept I-V characteristics of a Langmuir probe acquired at each spatial position and with the assumption of a Maxwellian distribution. The results show that the peripheral high temperature electrons in the magnetic nozzle originate from the upstream antenna location and are transported along the “connecting” magnetic field lines. Two-dimensional measurements of electron energy probability functions are also carried out in a second simplified laboratory device consisting of the source contiguously connected to the diffusion chamber: again the high temperature electrons are detected along the magnetic field lines intersecting the wall at the antenna location, even when the antenna location is shifted along the main axis. These results demonstrate that the peripheral energet...
53 citations
TL;DR: In this article, a rotating magnetic field (RMF) acceleration scheme was proposed to overcome the present problem of direct plasma-electrode interactions, leading to a short lifetime with a poor plasma performance due to contamination.
Abstract: As one of the electromagnetic plasma acceleration systems, we have proposed a rotating magnetic field (RMF) acceleration scheme to overcome the present problem of direct plasma-electrode interactions, leading to a short lifetime with a poor plasma performance due to contamination. In this scheme, we generate a plasma by a helicon wave excited by a radio frequency (rf) antenna which has no direct-contact with a plasma. Then, the produced plasma is accelerated by the axial Lorentz force fz = jθ × Br (jθ is an azimuthal current induced by RMF, and Br is an external radial magnetic field). Erosion of electrodes and contamination are not expected in this total system since RMF coils and an rf antenna do not have contact with the plasma directly. Here, we have measured the plasma parameters (electron density ne and axial ion velocity vi) to demonstrate this RMF acceleration scheme by the use of AC currents in two sets of opposing coils to generate a RMF. The maximum increasing rate Δvi /vi was ∼28% (maximum vi ...
17 citations
TL;DR: In this paper, the authors proposed a Rotating Magnetic Field (RMF) acceleration method as one of electrodeless plasma accelerations, which consists of two-pair, opposed, facing coils, and these antennas are outside of a discharge tube.
Abstract: We have proposed Rotating Magnetic Field (RMF) acceleration method as one of electrodeless plasma accelerations. In our experimental scheme, plasma generated by an rf (radio frequency) antenna, is accelerated by RMF antennas, which consist of two-pair, opposed, facing coils, and these antennas are outside of a discharge tube. Therefore, there is no wear of electrodes, degrading the propulsion performance. Here, we will introduce our RMF acceleration system developed, including the experimental device, e.g., external antennas, a tapered quartz tube, a vacuum chamber, external magnets, and a pumping system. In addition, we can change RMF operation parameters (RMF applied current IRMF and RMF current phase difference ϕ, focusing on RMF current frequency fRMF) by adjusting matching conditions of RMF, and investigate the dependencies on plasma parameters (electron density ne and ion velocity vi); e.g., higher increases of ne and vi (∼360 % and 55 %, respectively) than previous experimental results were obtaine...
16 citations
References
More filters
TL;DR: A review of plasma discharges applied to electric spacecraft propulsion can be found in this article, where the authors briefly report on the mature and flown technologies of gridded ion thrusters and Hall thrusters before exploring the recent yet immature technology of plasma thrusters based on expansion from low pressure high density inductively coupled and wave-excited plasma sources.
Abstract: This review presents the basics of plasma discharges applied to electric spacecraft propulsion. It briefly reports on the mature and flown technologies of gridded ion thrusters and Hall thrusters before exploring the recent yet immature technology of plasma thrusters based on expansion from low pressure high density inductively coupled and wave-excited plasma sources, e.g. the radiofrequency helicon source. Prototype development of plasma engines for future space travel is discussed using the example of the helicon double layer thruster. A summary of highlights in electric propulsion based space missions gives some insight into the challenges of future high power missions in more remote regions of space.
308 citations
"Thrust Characteristics of High-Dens..." refers background in this paper
...However, conventional electric thrusters, such as the ion engine, Hall thruster, and Magnetoplasmadynamic (MPD) thruster, suffer from the common problem of erosion of the electrodes that are in direct contact with the plasma, leading to reduction in their life span [4]....
[...]
TL;DR: In this paper, a standing helicon wave has been excited by applying a transverse rf field to a cylindrical plasma immersed in a steady axial magnetic field, and the predictions of the hydrodynamic theory are found to be inadequate in describing the damping.
282 citations
"Thrust Characteristics of High-Dens..." refers background in this paper
...H ELICON plasma is known to have a high production efficiency and uses an external magnetic field and RF power [1]....
[...]
TL;DR: A large literature on helicon discharges has evolved because of the numerous problems these discharges posed and the interesting physics found in their solutions as mentioned in this paper, and the semiconductor industry has not taken advantage of this, even since the possible use of permanent magnets for the B-field has been demonstrated.
Abstract: Helicon waves are waves in low-temperature, partially ionized plasmas in a dc magnetic field (B-field). The study of helicons involves both ion–neutral collisions and Larmor orbits, even when the B-field is uniform. Helicon discharges are ionized by helicon waves generated by a radiofrequency (RF) antenna. Interest in helicon discharges arose because of the high plasma densities they generate compared with other RF sources at comparable powers. The semiconductor industry has not taken advantage of this, even since the possible use of permanent magnets for the B-field has been demonstrated. Nonetheless, a large literature on helicons has evolved because of the numerous problems these discharges posed and the interesting physics found in their solutions.
159 citations
"Thrust Characteristics of High-Dens..." refers methods in this paper
..., strength of the magnetic field, filling pressure, and excitation frequency of RF power [2,3]), it is actively used in various fields such as plasma processing and electric propulsion....
[...]
TL;DR: It is demonstrated that the measured electron-diamagnetic-induced axial momentum increases with increasing magnetic field strength to approach the theoretical limit derived using an ideal nozzle approximation.
Abstract: Cross-field diffusion and plasma expansion in a rapidly diverging magnetic nozzle are controlled while maintaining constant plasma production in a contiguously attached radio frequency plasma source. It is demonstrated that the measured electron-diamagnetic-induced axial momentum increases with increasing magnetic field strength to approach the theoretical limit derived using an ideal nozzle approximation. The measured axial momentum exerted onto the axial and radial plasma source boundaries validate the prediction from a maximum electron pressure model on the back wall and from a zero net axial momentum model on the radial wall.
90 citations