RU13936U1 - RELATIVISTIC MAGNETRON - Google Patents

Abstract

A relativistic magnetron containing a grounded multi-cavity anode block, a drift tube, an axially arranged cathode connected by a cathode holder with a negative output of a power source and a magnetic system, characterized in that the cathode length is L = (1.4-2) L, where L- the length of the multi-cavity anode block, the free end of the cathode is located in the region of the drift tube with a radius of rounding of the end equal to the radius of the cathode.

Description

Relativistic magnetron

The invention relates to the field of relativistic high-frequency electronics and can be used to generate powerful microwave radiation. The practical use of microwave radiation imposes requirements for achieving maximum power due to the high efficiency of converting the energy of the electron beam into microwave energy.

A device is known - a relativistic magnetron, consisting of a multiresonator anode block, a cylindrical drift tube, an axially arranged cathode connected by a cathode holder with a negative terminal of a power source and a magnetic system A. Didenko et al. Investigation of the generation of powerful microwave frequencies using a relativistic magnetron. // Letters to the ZhTF, 1978, v. 4, jNb 3, p. 10-13.

As a power source of a relativistic magnetron, a high-current electron accelerator Vintizenko II can be used et al. Experimental studies of a multi-resonator high-current electron. // Letters to the ZhTF. 1983, vol. 9, jVs 8, p. 482-485. or linear induction accelerator Vasiliev VV, Vintienko II et al. Relativistic magnetron., operating in the train of pulses of pulses Pis.ma in ZhTF, 1987, v. 13, X 12, pp. 762-765. In these designs, the anode block and the probe are grounded, and a negative polarity pulse of d.igge.-and- is supplied to the cathode. 50200 NS, with an amplitude of 300-1000 kV. In a crossed electric radial iio.ic field with a cathode and anode and a magnetic field created by a magnetic system, the hücktroy emitted under the influence of explosive electron emission carry out:: nphen11e in two directions. As in a classical magnetron, electrons rotating azimuthally in the spokes, giving their energy to the energy of microwave radiation, carry out p; L anal drift to the anode. In the axial direction of the device, ropueiioix) current electrons emitted by the end of the cathode move. This current is formed by the action of a crossed electric edge radial field and a longitudinal magnetic field. ) The end-face currents are deposited on the surface of the drift pipe in the region of decreasing) m:;

MP to N 01 J 25/00

. , -y,) vi-i у ;,

/ pu p „-.- u)

where m, L is the mass and charge of the electron, c is the speed of light; at. 1 + C / 2 j V | b applied voltage between

cathode and anode; c / ,, is the inner diameter of the anode block; t / u is the outer diameter of the cathode A. Fedosov K calculation of the characteristics of an electron beam formed in diodes with magnetic insulation. Izv. Universities, Physics, 1977, X 10, p.134-135. For the actual dimensions of the magnetron used by us, mm and mm (the value of t4 was selected experimentally) and the voltage U 1000 kV, the Lorz value of “6.37 kA and the total efficiency device will be:

g I SEC I anon lie 1 ynpokJ (2

 p (g + g V / t + g f

-I J- anon / Tory JL akodi i

e21n

where / 7s 0.6n-0.8 - electrode efficiency magnetron, determined by its geometrical parameters (the number and size of resonators, etc.) At a microwave power of 1 GW, the anode current will be / a ,,, .. -1., 6 kA and the overall efficiency 12.6%.

The disadvantage of this device is the large loss of current in the axial direction, reducing the effectiveness of the relativistic magnetron.

Closest to the proposed device selected for the prototype Sulakshin A.S. Limiting the leakage of electron current from the interaction space of a relativistic magnetron. Tech magazine Physics, 1983, vol. 53, L 11, p. 226-2268. This relativistic magnetron contains a drift tube with an inner diameter exceeding the inner diameter of the anode block. In this case, the value of the end current is limited at the level of Bogdankevich L.S., Rukhadze A.A. stability of relativistic electron beams in plasma and the problem of critical currents. Advances in physical sciences. 1971. T. 133, L4, p. 603-640 / 77C- (y „-)

/ „„ :). 48 kA (...)

7 / 2/3, .3 / 2

However, a current of 6.37 kA is injected from the end of the cathode in accordance with (1). It is known that upon injection into the current drift tube more than a critical value at a certain distance from the injection plane, a virtual cathode is formed. Part of the current (/ ((//.) 0.8 kA is reflected from the virtual cathode and returns to the cathode anode gap. Some of the electrons of the reflected current can get into the correct phase of the spoke and give their energy to the electromagnetic wave. The wrong-phase electrons return to, taking the energy from the electromagnetic the waves.

Such a device allows you to slightly increase the efficiency of the relativistic magnetron in comparison with the analog device and the value of the efficiency until 47.

However, the task of increasing the efficiency magnetron due to the reduction of the end current does not lose its relevance.

To increase the efficiency of the magnetron, a relativistic magnetron device is proposed, containing, like the prototype, a multi-cavity anode block, a drift tube, a cathode connected by a cathode holder with a negative output of a power source, and a magnetic system. Unlike the prototype, the cathode has a length L (, - X) L greater than the length of the multi-cavity anode block 1 .. Thus, the end of the cathode is located in the region of the drift tube. In addition, the end of the cathode is rounded with a radius of rounding equal to the radius of the cathode. In FIG. shows the proposed device

The multi-cavity anode block is / electrically and mechanically connected to the drift tube 2 and connected to the earth potential of the power source. Arranged axially symmetrically inside the anode block, the cathode 3 is connected to the negative terminal of the power source by means of the cathode holder 4. To create a longitudinal magnetic field, a magnetic system 5 is used, which is fed from the ground power source. The end face of the cathode connected to the cathode holder is located in the plane of the end face of the magnetron

The device operates as follows. The power source of the magnetic system (pulse or constant) is first turned on. Then, from the magnetron power source, at the moment when the current of the magnetic system reaches its maximum value, a high voltage pulse of negative polarity is fed through the cathode to the holder to the cathode. Under the influence of high electric field strength 10 V / cm on

explosive electron emission is formed on the cathode surface E. Litvinov etc. Auto-emission and explosion-emission processes in vacuum discharges. Successes of physical sciences. 1983, t. 139, s. 265-302. In the crossed radial electric field between the cathode and the anode and the axial magnetic field of the magnetic system, the electrons imitated from the surface of the cathode, grouped into spokes, drift to the anode (as well as in the classical magnetron). With radial electron drift, the potential energy of electrons is converted to microwave energy. Since the free (unrelated to the cathode holder) end of the cathode is located in the drift tube region at a distance from the magnetron end (0,) L, the internal diameter of the drift tube significantly exceeds the inner diameter of the anode, the electric field strength in the region of the cathode end is much lower. Placing the end of the cathode at a distance greater than Q, 4L from the plane of the end of the magnetron reduces the influence of the edge radial electric field between the ends of the magnetron and the cathode.

The large length of the cathode necessitates an increase in the length of the region of a uniform magnetic field generated by the magnetic system. Otherwise, the end of the cathode may be in the edge field of the magnetic system. At values of the magnetic field below the critical value, a violation of the magnetic isolation of the gap will occur.

The injected current is:

 fflcMY.-Yjvi-iY ;,

/ neither.

I note that the formula for calculating / „„. Is given for the case of the formation of a continuous cylindrical electron beam. Due to the fulfillment of the end of the cathode rounded with a radius of curvature equal to the radius of the cathode, a continuous electron beam Isakov P.Ya. et al. Magnittoinsulated diode for producing a monoenergetic electron beam of nanosecond duration PTE, 1988, No. 2, pp. 27-29. The value of the efficiency magnetron in this case will be

„... 1.M ...,. 7o ..

 1+. 1,2) 1/1 + 2,

Tests of such a device were carried out using a sectional linear induction accelerator at a voltage of 400 kV at the cathode. The length of the multi-cavity anode was 72 mm. cathode lengths 125 and 140 mm. There was an increase in the efficiency of the relativistic magnetron by 1.3 times (the radiation power increased from 200 MW to l 260 MW, with equal geometrical dimensions of the magnetron, drift tube, cathode radius and the corresponding accelerator voltage and magnetic field induction.

Claims (1)

A relativistic magnetron containing a grounded multi-cavity anode block, a drift tube, an axially arranged cathode connected by a cathode holder with a negative output of a power source and a magnetic system, characterized in that the cathode length is L _k = (1.4-2) L _A , where L _A is the length of the multiresonator anode block, the free end of the cathode is located in the region of the drift tube with a radius of rounding of the end equal to the radius of the cathode.