JPS6263183A - Rf type ion source - Google Patents

Abstract

PURPOSE:To dissolve a weight increase due to a large size by applying a stretching function to an induction coil to make it reactance-variable and combin ing this coil and a frequency or capacitance-variable capacitor for impedance matching of plasma. CONSTITUTION:Electrons accelerated by an induction coil 6 collide against the Hg gas introduced into a discharge container 2, and ionized plasma is gener ated in a discharge chamber 8. Hg<+> ions are applied with kinetic energy by accelerating electrodes 3-5 to become thrust. In this case, a fixed jig 15 and a stretching jig 16 are provided so as to encircle the induction coil 6, and the coil 6 is made variable in length to constitute a reactance-variable induction coil. Accordingly, impedance matching of plasma is performed by combining the reactance-variable induction coil and the frequency or capacitance-variable capacitor, and a weight increase due to a large size is dissolved.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to an RF-type ion system for controlling the attitude of an artificial satellite.
The present invention relates to an RF type ion source suitable for engines.

[Technical background of the invention and its problems]

The configuration of a conventional RF (Radiofrequency) type ion engine is shown in FIG. 6, and the configuration of an RF oscillator is shown in FIG. collide to generate ionized plasma in the discharge chamber 8, Hg+ ions are given kinetic energy by the accelerating electrodes composed of electrodes 3 and 4.5, 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 induction 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 carry the high frequency current. The matching device 11 consists of a fixed capacitance 01 capacitor 13 and a variable capacitance 02 capacitor 12.
The amplifier 10 employs a class A amplifier in order to adjust the capacitance and frequency of the C2 capacitor 12 to change the zero frequency that matches the impedance of the plasma.

When an RF type ion engine is enlarged and launched, problems arise with the class A amplifier 10 of the RF oscillator and the variable capacitance capacitor 12 of the matching device 11. The power conversion efficiency of the class A amplifier 10 is 5
Since it is only about 0%, thermal problems will occur if the size is increased. Further, as the variable capacitance capacitor 12 becomes larger, the voltage becomes higher and the weight increases rapidly.

[Purpose of the invention]

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide an RF type ion source that performs plasma impedance matching that does not cause a rapid increase in weight as the size increases.

[Summary of the invention]

The present invention is an RF type ion source characterized in that an induction coil is given an expansion and contraction function to make the reactance variable, and in combination with a variable frequency or capacitance capacitor, plasma impedance matching is achieved6. According to the present invention, plasma impedance matching is performed using a variable reactance induction coil and frequency, eliminating the problem of variable capacitance capacitors.
Since the temperature can be changed to 100%, thermal problems are eliminated.

[Embodiments of the invention]

Examples of the present invention will be described in detail below. Note that the same reference numerals are given to the parts having the same configuration as those of the conventional device, and the explanation thereof will be omitted. As shown in FIG. 1, a variable reactance induction coil is constructed by making the length of the induction coil variable by a telescoping jig 16 for expanding and contracting the induction coil 6 and a fixing jig 15 for fixing the induction coil 6. do. The fixing jig 15 may be installed at any number of locations to the extent that the induction coil 6 is not displaced.
The figure shows an enlarged view of the extension jig 16.

There are three locations in total. The coil 6 is made of copper, the fixing jig 15 is made of ceramic, and a ceramic insulator is inserted into the contact portion of the extensible jig 16 with the coil 6. Further, as shown in FIG. 3, the variable reactance induction coil may be configured only with a fixing jig 15 that maintains a predetermined gap and tightens.

Fig. 4 is a block diagram of an RF oscillation system in which impedance matching of plasma is achieved using a beam actance variable induction coil 6. It is composed of a high frequency generator 9 with variable frequency, an amplifier 10, and capacitors 12 and 13 with fixed capacitance. An RF oscillator is constituted by the matching device 11.

Plasma impedance matching is performed by adjusting the reactance of the variable frequency and actance induction coil 6.

C2 Capacitor 1 with variable capacitance in the conventional example shown in Figure 7
2 has been changed to a fixed capacitor in Fig. 4.

FIG. 5 is a block diagram of another RF oscillator.

An RF oscillation unit is composed of a high frequency generator 9 with a fixed frequency, a class C amplifier 14, and a matching box 11 including at least one variable capacitance capacitor. Plasma impedance matching is performed by adjusting the capacitance of the variable capacitor 12 and the reactance of the variable actance induction coil 6. Since the frequency is fixed, the amplifier is changed to a class 0 amplifier with a power conversion efficiency of about 80%.

In this embodiment, two methods of varying the reactance of the induction coil 6 have been described, but the point is that the induction coil 6 only needs to be able to expand and contract, and is not limited to the above embodiments.

In addition, as an example of the matching device 11, the case of two capacitors 12.13 is described, but the point is that the circuit is not limited to this embodiment as long as it can match the impedance of the plasma. is used, but
It is not limited to Hg gas.

Although the present invention has been described with respect to an RF type ion engine, it can be applied to all devices using an RF type discharge chamber. The same applies to type ion sources.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional perspective view showing an embodiment of the invention, FIG. 2 is a sectional view of the embodiment of the invention, FIG. 3 is a sectional view of another embodiment of the invention, and FIGS. FIG. 5 is a block diagram of another RF oscillation tree of the present invention, FIG. 6 is a sectional view of a conventional RF type ion engine, and FIG. 7 is a block diagram of a conventional RF oscillator. 2...Discharge vessel 3,4.5...Electrode 17...
・Gas diffusion plate 6...Inductor coil 7...
- Neutralizer 8... Discharge chamber 9... High frequency generator 10... Class A amplifier 11... Matching box 12
．． 13... Capacitor 14... Class C amplifier 15... Induction coil fixing jig 16... Induction coil expansion/contraction jig Agent Patent attorney Nori Chika
Ken Yudo Kikuo Takehana Figure 1

Claims (4)

[Claims] (1) In an ion source consisting of a gas introduction system, a discharge vessel, an electrode, an induction coil, a neutralizer, an RF oscillator, an acceleration power source, etc., the induction coil is given an expansion and contraction function to make the reactance variable. An RF type ion source characterized by the following. (2) The RF type ion source according to claim 1, wherein the variable reactance induction coil is constituted by an induction coil, a telescoping jig, and a fixing jig. (3) The RF oscillator consists of a variable-frequency high-frequency generator, an amplifier, and a matching device consisting only of a capacitor with a fixed capacity.
The RF type ion source according to claim 1, characterized in that the impedance matching of the plasma is performed by adjusting the frequency and the reactance of the variable reactance induction coil. (4) The RF oscillator consists of a high frequency generator with a fixed frequency, an amplifier, and a matching device including at least one variable capacitance capacitor, and the capacitance of the variable capacitor and the reactance of the variable reactance induction coil are adjusted to match the impedance of the plasma. The RF type ion source according to claim 1, characterized in that the RF type ion source is configured to perform the following.