JPH01213998A - Neutral particle incidence device utilizing negative ion source - Google Patents

Abstract

PURPOSE:To overcome the technical difficulties in the manufacture of an inverter by combining intermittent outputs from a charged particle collector for positive and negative particles to form an AC voltage, wherein the outputs are produced by intermittently operating a negative ion source. CONSTITUTION:An output from an inverter 17, which is a high frequency square wave AC voltage, is brought into a square wave AC voltage with an amplitude of about 1MV by a step-up transformer 18, and this voltage is applied to the accelerating electrodes 6, 6' without any change. A negative ion source, having a kind or rectifying characteristic, output a negative heavy hydrogen ion beam D<-> only when a negative voltage is applied to the accelerating electrode 6 or a positive voltage is applied to the acceleration electrode 6'. The negative heavy hydrogen ion beam D<->, positive heavy hydrogen ion beam D<+>, and neutral heavy hydrogen beam D<0> are therefore all caused to be intermittent beams of about 1KHz. Output voltages produced by these beams are combined via reverse current preventing diodes 19, 20 after their phase are shifted by 180 deg. from each other, so that the resultant voltage becomes a high frequency square wave AC voltage of about 1KHz having an amplitude of about 1MV. Thus, th inverter 17, 22 can be manufactured easily.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a neutral particle injection device using a negative ion source. Specifically, the present invention relates to a neutral particle injection device using a negative ion source, which is being considered for use in plasma heating and current drive of future nuclear fusion reactors.

FIG. 1 is an example of a neutral particle injection device using a conventional negative ion source. The explanation will be given below using the numbers in the figure.

Deuterium gas is introduced into the arc vessel 2 by the deuterium gas introduction device 1, the filament 4 is heated by the filament power supply 3, and the filament 4 and the arc vessel 2 are heated by the arc power supply 5.
When a voltage is applied during this period, deuterium arc discharge occurs in the arc vessel 2.

Deuterium arc discharge consists of positive and negative deuterium ions and electrons, which are indicated by symbols d" and d-1e, respectively in the figure. Approximately IMV is generated between accelerating electrodes 6 and 6' with holes by accelerating power source 7. When a DC voltage is applied with a negative polarity to the accelerating electrode 6 and a positive polarity to the accelerating electrode 6', only deuterium negative ions d- and electrons e are extracted through the hole of the accelerating electrode 6. Of these, the electron e is absorbed by the electron absorption device. 8, and only the deuterium negative ions d- are accelerated to form a deuterium negative ion beam D-
becomes. The deuterium negative ion beam D= requires a current density of about 59 mA/csA, and a total of about 10 OA.

In addition, the accelerating electrode 6.6 to which a DC voltage of about IMV is applied
Since discharge breakdown occasionally occurs between '', in order to prevent the accelerating electrode 6.6' from being damaged by the continuous current from the accelerating power source 7, a high-speed switch 9 that can cut off the current within about 100 ps is installed. It is a provision.

Of the above explanations, 2.4.6.6' and 8 are collectively referred to as a negative ion source. In addition, since the deuterium negative ion d- is electrostatically accelerated at the accelerating electrode 6.6,
．． 6 is called an electrostatic accelerating electrode.

The deuterium negative ion beam D- is neutralized in a neutralization cell 10. Deuterium gas is introduced into the neutralization cell 10 from the deuterium gas introduction device 1 . The neutralization cell 10 utilizes the elementary process of charge exchange between the deuterium negative ion beam D- and deuterium gas, so that all of the deuterium negative ion beam D- incident on the neutralization cell 10 is neutral. Only about 54% of it is neutralized and becomes a deuterium neutral beam1)
0, while about 23% remains as the deuterium negative ion beam D-, and the remaining 23% remains as the deuterium positive ion beam D0.
becomes. These deuterium positive ion beam D0 and deuterium negative ion beam D- are useless as a neutral particle injection device, so by applying a magnetic field or electric field to the exit side of the neutralization cell 10, deuterium ion beam D0 and deuterium negative ion beam D- are used. It is separated from the positive deuterium ion beam Do and collected by the deuterium positive ion beam collection electrode 1) and the deuterium negative ion beam collection electrode 12, respectively.

Due to the charges of the recovered deuterium positive ion beam D' and deuterium negative ion beam D-, the recovery capacitors 13 and 14 are charged to near IMV with the polarities shown in the figure. This DC voltage is converted into AC by an inverter 15, then stepped down by a step-down transformer 16, and the energy is regenerated into a commercial AC line.

(Problems to be Solved by the Invention) The conventional neutral particle injection device using a negative ion source as described above has the following drawbacks.

Second, it is technically difficult to manufacture the high-speed switch 9 that cuts off the high-voltage DC voltage of approximately IMV.

Another problem is that it is technically difficult to manufacture the inverter 15 that converts a high DC voltage of plus or minus IMV into an AC voltage.

An object of the present invention is to provide a neutral particle injection device using a negative ion source that overcomes the drawbacks of the conventional systems as described above.

(Means for Solving the Problems) As a result of intensive research, the inventors of the present invention have found that (1) a negative ion source characterized by applying an alternating current voltage to an electrostatic accelerating electrode; and (2) a neutral particle injection device using a negative ion source having two types of positive and negative charged particle collection devices, two types of positive and negative particles can be obtained by intermittent operation of the negative ion source. This objective has been achieved by a neutral particle injection device using a negative ion source, which is characterized in that the intermittent outputs of the charged particle collection device are combined to produce an alternating current voltage.

(Example) Next, the present invention will be specifically explained with reference to the drawings by way of an example. However, the present invention is not limited to the examples.

FIG. 2 shows an embodiment of the invention.

In Figure 2, 1 to 6.6゛, 8.10.1). 12 and 1
6 is the same as in FIG. 17 in Figure 2 is the commercial frequency (5
This is an inverter that converts a voltage of 0 Hz or 60 Hz into a rectangular wave voltage with a high frequency of about I KHz.

The high frequency rectangular wave AC voltage which is the output of the inverter 17 is boosted to a rectangular wave AC voltage of plus or minus approximately IMV by the step-up transformer 18, and the voltage remains unchanged at the accelerating electrode 6.6.
is applied to ゛. An alternating current voltage will be applied to the accelerating electrode 6.6'', but the negative ion source has a kind of rectifying property, so when a negative voltage is applied to the accelerating electrode 6 and a positive voltage is applied to the accelerating electrode 6'', Therefore, the deuterium negative ion beam D-, the deuterium positive ion beam D', and the deuterium neutral beam DO are all
It becomes an intermittent beam of about KHz. Further, the output voltage of the deuterium positive ion collection electrode 1) and the deuterium negative ion collection electrode 12 is also about IMV, and is an intermittent output of about I KHz.

These output voltages are controlled by a diode 19.20 for backflow prevention.
synthesized via. Note that these output voltages are combined after being shifted in phase by 180° from each other in the slow wave circuit 21, so the combined voltage is approximately plus or minus I MV,
It becomes a rectangular wave alternating current voltage with a high frequency of about I KHz. Is this rectangular wave AC voltage used as it is in the negative ion source?
Alternatively, the voltage is lowered by the step-down transformer 16 and the voltage is lowered by the inverter 2.
2, it is converted to a commercial frequency and the energy is regenerated into a commercial AC line.

(effect) According to the present invention as described above, the following advantages arise.

One is that unlike the inverter 15 in FIG. 1, the inverter 17.22 in FIG. 2 is easy to manufacture because it does not require a high voltage of about IMV. The high-speed switch 9 that cuts off the voltage of about IMV in Figure 1, which is technically difficult, can cut off the output at high speed.
is not necessary.

When the present invention is applied, the deuterium negative ion beam D- becomes an intermittent beam, so the time average current density becomes about half of the maximum value.

However, depending on the operating conditions of the negative ion source, the current density of the deuterium negative ion beam D- may be approximately 2a+ immediately after the start of operation.
It is experimentally known that it becomes extremely large during s.

Therefore, if intermittent operation is performed at about IKH2 as in the present invention, there is a possibility that a deuterium negative ion beam D- with a high current density can be obtained.

In FIG. 2, there is a possibility that the amount of positive and negative charges collected by the positive deuterium ion collection electrode 1) and the negative deuterium ion collection electrode 12 will be unbalanced. In that case, the DC component represented by the average of both is not regenerated through the step-down transformer 16 and the inverter 22, and becomes a loss. However, it is known that the ratio of the positive and negative charges can be adjusted depending on the amount of deuterium gas introduced from the deuterium gas introduction device 1 into the neutralization cell 10. Therefore, by appropriately selecting the amount of deuterium gas introduced, it is possible to balance the positive and negative charges and provide an apparatus with less loss.

In the example shown in Fig. 2, a slow wave circuit is used to synthesize the output voltages of the deuterium positive ion collection electrode 1) and the deuterium negative ion collection electrode 12 to create an alternating current voltage, but the same output voltage is generated intermittently at about I KHz. An alternating current voltage may be used by using a resonant circuit that resonates with the voltage.

As described above, according to the present invention, it is possible to create a neutral particle injection device using a negative ion source with few technical difficulties.

[Brief explanation of the drawing]

FIGS. 1 and 2 are examples of neutral particle injection devices using negative ion sources according to the conventional scheme and the present invention, respectively. 1 Deuterium gas introduction device 2 Arc vessel 3 Filament power source 4 Filament 5 Arc power source 6.6゛ Acceleration electrode 7 Acceleration power source 8 Electron absorption device 9 High speed switch 10 Neutralization cell 1) Deuterium positive ion recovery electrode 12
Deuterium negative ion recovery electrode 13.14 Recovery capacitor 15.17.22 Inverter 16 8s pressure transformer 18 Step-up transformer 19.20 Diode 21 Slow wave circuit DO Deuterium positive ion d - Deuterium negative ion e Electron Do Deuterium positive ion Beam D - Deuterium negative ion beam D0 Deuterium neutral ion beam support f drawing 2z

Claims (2)

[Claims] (1) A neutral particle injection device using a negative ion source characterized by applying an alternating current voltage to an electrostatic accelerating electrode. (2) In a neutral particle injection device using a negative ion source that has two types of positive and negative charged particle collection devices, intermittent operation of the two types of positive and negative charged particle collection devices is obtained by intermittent operation of the negative ion source. A neutral particle injection device using a negative ion source characterized by generating an alternating current voltage by synthesizing the output.