JPH02305376A - Hollow cathode of ion thrustor - Google Patents

Abstract

PURPOSE:To obtain great level of electric current securing smaller voltage and quick response of discharge by after performing discharge in one insert heated by a heater, continuing discharge in the other insert heated by the discharge energy. CONSTITUTION:In order to drive an ion thrustor, a second insert 16 is heated at first by a heater 18, and an electron is emitted from an inner wall thereof, so as to start discharge between this and a keeper 15, while a first insert 11 is heated by the energy concomitant with the discharge. Discharge is then started between the first insert 11 that reaches a predetermined operational temperature, and the keeper 15. Pressure of the operational gas in each insert 11, 16 is increased by an orifice 12 so as to promote discharge. To a cathode 14 of an ion thrustor main body 13, positive electric potential is added to each insert 11, 16, and by generating discharge between them, the ion thrustor is driven.

Description

[Detailed Description of the Invention] "Objective of the Invention" (Industrial Application Field) The present invention relates to an ion thruster that is mounted on a spacecraft such as an artificial satellite and used as a secondary propulsion system.
In particular, it relates to a hollow cathode used as an electron source.

(Prior Art) In recent years, in the field of space development, long-life, large-sized spacecraft have been developed, and along with this, ion thrusters with large specific impulses have been developed. and,
The next requirement for such an ion thruster is to increase its thrust while ensuring weight reduction.

In order to realize this request, the hollow cathode used as the electron source for ion generation and ion beam neutralization must be able to supply large currents of electrons without increasing its weight including its power source. configuration is required.

Figure 3 shows a hollow cathode of a conventional electron impact type ion thruster.A temperature control heater 3 is attached to the insert 2 around the insert 2 to which the working gas 1 is supplied, and an electron emitting device is attached to the emitting end of the insert 2. An orifice 4 is installed for the purpose. This orifice 4 is provided facing the anode 6 of the ion thruster body 5, and a keeper 7 is interposed between the tip thereof and the ion thruster body 5. This keeper 7 is set at a positive potential with respect to the insert 2 and orifice 4. Further, the insert 2 is impregnated with, for example, oxidized barium so that electrons can be easily released.

In the above configuration, when driving the ion thruster, the heater 3 is first driven to control heating of the insert 2 to a temperature at which electrons can be emitted. When the insert 2 is heated to a predetermined operating temperature, the insert 2 emits electrons from its surface and starts discharging with the keeper 7. At this time, the pressure of the working gas 1 inside the insert 2 is increased by the orifice 4, and its discharge is promoted.

At the same time, a positive potential is applied to the anode 6 with respect to the insert 2 and the orifice 4. As a result, insert 2
A discharge occurs between the anode 6 of the ion thruster main body 5 and the ion thruster is operated.

Here, the operating temperature of the insert 2 is maintained by the discharge energy accompanying the discharge generated between the insert 2 and the anode 6 of the ion thruster main body 5, and the discharge operation is maintained with the heater 3 stopped.

However, in the hollow cathode of the electron impact type ion thruster, the current value corresponds to the surface area of the inner wall of the insert 2 that forms the electron emitting surface, so in an attempt to increase the current value, the size of the insert 2 is increased. If the molding is promoted, the heater 3 for heating control must be made large in size to correspond to the surface area of the insert 2, which requires a high-power heater power source, leading to an increase in weight. Moreover, according to this, as the surface area of the insert 2 increases, it takes a long time to control the heating, and there is also a problem that the quick response is reduced.

(Means for solving the problem) As described above, in the hollow cathode of the conventional electron impact type ion thruster, increasing the current requires a high-power power source, increases the weight, and increases the operating temperature. The problem is that it takes a long time to heat up and the promptness of discharge ignition decreases.

This invention was made in view of the above circumstances, and aims to provide a hollow cathode for an ion thruster that can obtain a large current while reducing the power consumption and ensuring the prompt response of discharge ignition. do.

[Structure of the Invention (Means for Solving the Problems) This invention comprises: - a first insert to which working gas is supplied from the blade end; and one electrode of the ion thruster main body at the other end of the first insert. an orifice that serves as an electron emission opening provided opposite to the ion thruster; a keeper that is interposed between the orifice and one electrode of the ion thruster body and forms an electrode that extracts electrons; and the other of the first inserts. a second hole provided on the inner wall of the end corresponding to the orifice;
The hollow cathode of the ion thruster includes a second insert and heating means for heating the second insert and igniting the discharge.

(Function) According to the above configuration, when the heater controls the heating of the second insert to the operating temperature, a discharge is first ignited within the second insert, and the first insert is heated to the operating temperature by the discharge energy accompanying the discharge. and a discharge occurs within the first insert including the second insert. Therefore,
A large current corresponding to the first insert can be obtained with enough power to heat the second insert.
゛(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a hollow cathode of an ion thruster according to an embodiment of the present invention, in which a first insert 11 to which working gas 10 is supplied has an orifice 12 for electron emission attached to its emission end. The orifice 12 is provided facing the anode 14 of the ion thruster body 3, and a keeper 15 is interposed between the tip thereof and the ion thruster body 13. This keeper 15 is set at a positive potential with respect to the first insert 11 and the orifice 12.

Further, a second insert 16 having a small surface area is inserted into the discharge end side of the first insert 11 at a predetermined interval with a heat insulating material 17 interposed therebetween.・1
A heating control no-heater 18 is attached to the periphery of the heater 6 . This second insert] 6 is the first insert!・
1] and the orifice 12, and set to the same potential as these. The insert 16 is impregnated with, for example, barium oxide to release electrons.

In the above configuration, when driving the ion thruster, the heater 18 is first driven to control heating of the second insert 16 to a temperature at which electrons can be emitted. Then, when the second insert 16 reaches a predetermined operating temperature, the second insert 16
As shown in Figure (a), electrons are emitted from the inner wall and a discharge is started between the keeper 15 and the thermal radiation from the plasma accompanying the discharge and the discharge energy due to ion collisions, which causes the first Heat the insert] 1. Then, when the first insert reaches a predetermined operating temperature, as shown in FIG. 2(b), the second insert]
6, discharge starts between the keeper 15 and the keeper 15. At this time, the pressure of the working gas 10 inside the first and second inserts 1.1.16 is increased by the orifice 12, and the discharge thereof is promoted.

At the same time, the anode 14 of the ion thruster main body 13 has a first
and a positive potential is applied to the second insert 11.16. As a result, the first and second inserts 11.
16 and the anode 14 of the ion thruster body 13.
．． A discharge occurs and the ion thruster is activated.

Here, the operating temperature of the first and second inserts 11.16 is maintained by the discharge energy accompanying the discharge generated between the first and second inserts 11.16 and the anode 14 of the ion thruster body 13,
The discharging operation is maintained while the drive of the heater] 8 is stopped.

In this way, the hollow cathode of the ion thruster is provided with the second insert 16 corresponding to the orifice 12 at the discharge end of the first insert 11, and the second insert 16 is heated with the heater 18 to ignite the discharge. , the first insert 11 is heated to an operating temperature by the discharge energy accompanying the discharge, and the first insert 11 is configured to generate a discharge. According to this, the second insert 1
With enough power to heat and control the first inserter l-
11, it is possible to obtain as large a current value as possible without increasing the heater power. In addition, by simply controlling the heating of the second insert [6], which has a small area, to the operating temperature, it is possible to improve the responsiveness of discharge ignition as much as possible.

Note that this invention is not limited to the above embodiments, but also includes
It goes without saying that various modifications can be made without departing from the spirit of the invention.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to provide a hollow cathode for an ion thruster that can obtain a large current while reducing power consumption and ensuring prompt response of discharge ignition. I can do it.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing a hollow cathode of an ion thruster according to an embodiment of the present invention, Fig. 2 is a diagram shown to explain the operation of Fig. 1, and Fig. 3 is a diagram showing a conventional electron impact type ion thruster. FIG. 3 is a configuration diagram showing a hollow cathode of a thruster. 10... Working gas, 11... First insert, 1
2... Orifice, 13... Ion thruster body,
14...Anode, 15...Keeper, 16...Second insert, 17...Insulating material, 18...Heater.

Claims (1)

[Claims] A first insert to which working gas is supplied from one end, and an electron emission port provided at the other end of the first insert facing one electrode of the ion thruster body. an orifice, a keeper interposed between the orifice and one electrode of the ion thruster body and forming an electrode for extracting electrons, and a keeper provided on an inner wall at the other end of the first insert in correspondence with the orifice. A hollow cathode for an ion thruster, comprising: a second insert; and heating means for heating the second insert to perform discharge ignition.