JPS6263182A - Rf type ion source - Google Patents

Abstract

PURPOSE:To make vacuum capacitors lightweight and make an RF type ion source large-sized by providing an electrode mechanism on part of a discharge container to constitute vacuum capacitors. CONSTITUTION:Electrons accelerated by an induction coil 6 collide against the Hg gas 19 introducted into a discharge container 1, and ionized plasma is generated in a discharge chamber 8. Hg<+> ions are applied with kinetic energy by accelerating electrodes 2-4 to become thrust. In this case, multiple electrodes are provided outside the discharge container 1 to constitute vacuum capacitors 12, 13, which are covered with a sealed container 14. The inter-electrode distance of the vacuum capacitor 12 is made variable to constitute a matching unit. Accordingly, the matching unit constituting part of an RF oscillator supplying a high-frequency current to the induction coil 6 is made part of the discharge container 1, thus vacuum capacitors are made lightweight.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an RF ion source suitable for an RF ion engine that controls the attitude of one artificial satellite.

[Technical background of the invention and its problems]

The configuration of a conventional RF (Radiofrequency) type ion engine is shown in FIG. 3, and the configuration of an RF oscillator is shown in FIG. 4. collide to generate ionized plasma in the discharge chamber 8, Hg+ ions are given kinetic energy by the accelerating electrodes composed of electrodes 2 and 3.4, and are neutralized by electrons emitted from the neutralizer 7. After that, it is released and becomes the thrust of the ion engine.

The RF oscillator that supplies high frequency current to the inductor coil 6 is composed of a high frequency generator 9, a class A amplifier 10, and a matching box 11, and uses a coaxial cable to convey the high frequency current. The matching box 11 is a C1 capacitor 13 with a fixed capacity.
and a variable capacitance 02 capacitor 12, and the capacitance and frequency of the C2 capacitor 12 are adjusted to match the impedance of the plasma.

In order to change the frequency, the amplifier 10 employs a class A amplifier. The weight of the 01 capacitor 13 with a fixed capacity is not so much of a problem, but the weight of the 03 capacitor with a variable capacity is a problem.

In order to increase the size of the RF type ion engine, it is necessary to improve the withstand voltage characteristics of the capacitors C1 and C, which is expected to further increase the weight, which is a major problem.

[Object of the Invention] The present invention was made in view of the above circumstances, and an object of the present invention is to provide an RF type ion source that can be made larger by reducing the weight of the capacitor C□s C. .

[Summary of the invention]

The present invention is an RF type ion source characterized in that a discharge part and a matching device, which were configured separately, are integrated by providing a vacuum capacitor part in a part of the discharge vessel.

〔Effect of the invention〕

According to the present invention, the matching box is a part of the discharge vessel, which can significantly reduce the weight, and the capacitor is located near the inductor coil, so the lead wire is short and there is less abnormal oscillation and electromagnetic interference due to stray capacitance. A possible RF type ion source can be constructed.

[Embodiments of the invention]

Examples of the present invention will be described in detail below. Note that portions iI whose configurations are the same as those of the conventional device are designated by the same reference numerals, and the description thereof will be omitted. As shown in Figures 1 and 2,
By providing three electrodes on the outside of the discharge vessel 1 to form a vacuum capacitor 12, 13 and covering it with a sealed vessel 14, if the distance between the electrodes of the vacuum capacitor 12 is made variable, the matching device 1
1 has been configured. The sealed container 14 may be omitted if there is no need for electromagnetic shielding, during experiments on the ground.
Without the sealed container 14, the vacuum capacitors 12, 13 may come into contact with the atmosphere. At this time, sealed container 1
4 must be able to withstand atmospheric pressure.

Another embodiment is shown in FIG. 3.As shown in FIG. 3, three electrodes are provided inside the discharge vessel 1, and the vacuum capacitor 1 is
2.13 and the distance between the electrodes of the vacuum capacitor 12 is made variable, the matching device 11 is constructed. If there is a risk that Hg gas may harm the electrode, cover it with a sealed container. If there is no risk that Hg gas may harm the electrode, the function of the gas diffusion plate 5 can be replaced by a vacuum capacitor 12.1.
It is also possible to have it on the third electrode.

In Figures 1 to 3, a vacuum capacitor 12 with three electrodes is shown.
．． 13, but the point is that it is sufficient if a vacuum capacitor can be constructed, and the position shown in Figures 2 and 3,
It is not limited to the shape or the number of electrodes. In addition, the case where the matching device 11 is made up of two vacuum capacitors 12- and 13 has been explained, but the point is that any matching device that can achieve impedance matching with the plasma is sufficient, and the number of vacuum capacitors is not limited to two. do not have. A light weight fixed capacity capacitor may be provided separately from the discharge section as is conventional.

Although ng is used as the introduced gas, it is not limited to l1g gas.

Although the invention has been described with respect to an RF type ion engine, it is applicable to any device using an RF type discharge chamber. - For example, the same applies to the RF type ion source of the particle injection device for plasma heating used in the fusion.

[Brief Description of the Drawings] Fig. 1 is a partially cutaway perspective view showing an embodiment of the present invention, Fig. 2 is a sectional view thereof, and Fig. 3 is a sectional view showing another embodiment of the invention. Figure 4 is a cross-sectional view of a conventional RF type ion engine.
FIG. 5 is a block diagram of a conventional RF oscillator. 1...Discharge vessel 2,3.4...Acceleration electrode 5...Gas diffusion plate 6...Induction coil 7...Neutralizer 8...Discharge chamber 9...High frequency generator 10 ... Class A amplifier 11 ... Matching box 12 ... Variable capacitor 13 ... Fixed capacitor 14 ... Sealed container agent Patent attorney
Nori Chika Ken Yudo Takehana Kikuo No. 1 Diagram==Ro■Ro■Ro 3

Claims (6)

[Claims] (1) In an ion source consisting of a gas introduction system, a discharge vessel, an electrode, an induction coil provided on the outer periphery of the vessel, a neutralizer, an RF oscillator, an acceleration power source, etc., an electrode mechanism is installed in a part of the discharge vessel. An RF type ion source characterized in that a vacuum capacitor is configured by providing a vacuum capacitor. (2) The RF type ion source according to claim 1, wherein one of the vacuum capacitors has a variable capacity. (3) The RF type ion source according to claim 1, characterized in that a vacuum capacitor is disposed outside the discharge vessel. (4) The RF type ion source according to claim 3, wherein the vacuum condenser is covered with a sealed container. (5) The RF type ion source according to claim 1, characterized in that a vacuum capacitor is disposed inside the discharge vessel. (6) The RF type ion source according to claim 5, characterized in that the vacuum condenser has a gas diffusion function.