RU2704523C1 - Device for creation of adjustable thrust force in electric ion engine - Google Patents

Abstract

FIELD: rocket equipment.

SUBSTANCE: invention relates to rocket engineering, in particular to electric ion engines equipped with thrust control device due to additional acceleration of ions in high-frequency field. Device for creation of controlled thrust force in electric ion engine comprises gas-discharge chamber, ending with screen electrode, multibeam ion-optical system (IOS) consisting of a series of flat electrodes with spaced apart holes connected in series with gaps and connected to sources of constant accelerating and braking voltage, high-frequency oscillation generator having two high-frequency communication lines. One of the lines (input) includes an input attenuator and is connected by means of an input turn of communication to the input parallel resonant circuit tuned to the operating frequency of the generator F₀ and connected to accelerating and input control electrodes of multibeam IOS installed in input section of device. Second (output) high-frequency line includes phase shifter and is connected by means of output communication turn with output parallel resonant circuit, also tuned to operating frequency of generator F₀ and connected to output control electrode installed in device output section immediately before slowing electrode. Introduced are additional alternating, control and focusing electrodes with drift holes symmetrically separated from each other by screening electrodes; wherein additional control electrodes located in the input section of the device are connected to two additional parallel oscillatory circuits.

EFFECT: using invention provides higher and smoothly controlled speed of ion stream, providing increase in traction force and its adjustment in wide range, and increased durability of the device due to reduced erosion and probability of destruction of electrodes of the ion-optical system (IOS).

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Description

The invention relates to rocket technology, in particular to electric ion engines.

A device is known for creating an adjustable traction force in an electric rocket engine (US patent No. 4838021, IPC: F03H 1/00), comprising an ionization chamber and an ion-optical system with two electrodes (screen and accelerating), between which a constant accelerating difference is applied potentials. The modulation of the multipath ion current is carried out by pulse modulation of the discharge current in the ionization chamber.

However, the implementation of this device requires a bulky electric energy storage device (usually a large capacitor bank), as well as a complex switching unit for exciting a pulse discharge, which includes a microcontroller.

There is also known a device for accelerating a spacecraft with a stream of charged particles (patent for invention RU No. 2104411, IPC: F03H 1/00, B64G 1/40) containing a plasma source (ionizer) and a multi-beam ion-optical system having three electrodes in series on away from each other, and the first electrode (screen) is the end wall of the ionizer and is positively charged. The second, negatively charged electrode, serves to accelerate the ion flow. To improve the structure of the ion flux, after the accelerating electrode, a third slowing electrode is installed, which slows down the fastest ions. The multipath flow is formed due to the fact that the electrodes of the ion-optical system have a set of separate longitudinal channels for the passage of individual ion beams, and the channel centers and the centers of the focusing surfaces on the outside of the screen electrode corresponding to these channels are located on more than one concentric circles relative to the axis of the engine.

The disadvantage of this device is that in order to achieve a high speed of the ion flux in the accelerating system between the screen and accelerating electrodes, it is necessary to maintain a high accelerating voltage (10 ... 50 kV), which is associated with the danger of electrical breakdown in the insulating elements separating the electrodes or directly in the working gap. In addition, the ingress of ions on the walls of the passage channels can cause destruction of the electrodes of the jet ion engine.

To eliminate this drawback in US patent No. 6318069 "Ion thruster having grids made of oriented pyrolytic graphite" it is proposed to make a grid of a three-electrode ion engine of pyrolytic graphite.

A further increase in ion flow rate is possible in a four-mesh ion engine (see Feam D.G. "The use of ion thruster for orbit raising // J. Brit. Interplan Soc. V. 33, 1980-PP 129-137).

In this device, ions are accelerated in two stages. The plasma has a potential approximately equal to the anode U _a = + (20 ... 30) kV. At the first stage of acceleration, ions are removed from the gas discharge chamber using the first two grids (screen and extraction) with the potential difference between them being limited to a value less than 0.85 U _a . This is necessary to prevent excessive curvature of the plasma surface and, accordingly, to eliminate the directed ingress of part of the ions onto the extraction grid.

The second stage of acceleration occurs between two sequentially located electrodes (extracting and accelerating) due to the presence of a constant potential on the accelerating electrode, reaching a value of approximately - 0.07 U _a . These electrodes are spaced apart from each other, eliminating the possibility of electrical breakdown. The fourth electrode in this device plays the same role as the third (decelerating) electrode in the three-electrode circuit. It serves zero potential. This electrode reduces the divergence of ion beams associated with the influence of space charge. Ultimately, at the exit from the engine, ions can accelerate to speeds of the order of 150-200 (km / s).

However, in this engine, adjusting the traction force is also difficult, as in the case of a two-electrode accelerating system. In this case, the thrust impulse can only be changed by varying the frequency of switching on the ion engine, as well as by changing the pulse duration due to pulse modulation of the discharge current in the ionization chamber.

To perform space flights to distant planets, jet engines with an ion flux velocity of more than 200 (km / s) are required with a broadly controlled thrust force. This can be achieved in electric ion engines, allowing you to adjust the traction due to the additional acceleration of ions in a high-frequency field.

The closest analogue to the claimed technical solution is a device for creating an adjustable traction force in an electric ion motor (utility model patent RU No. 73405, IPC: F03H 1/00, B64G 1/40), containing a gas discharge chamber ending with a screen electrode, a multipath ion -optical system (IOS), consisting of a series of consecutively installed flat electrodes with span holes connected to sources of constant accelerating and braking voltage, a high-frequency oscillation generator having two high-frequency communication lines, one of which (input) includes an attenuator and is connected using the first turn of communication with an input parallel resonant circuit tuned to the operating frequency of the generator and connected to the accelerating and input control electrodes of the multi-beam IOS installed in the input section of the device, and the second high-frequency line includes a phase shifter and is connected via an output coupling loop to an output parallel resonant circuit, also tuned to the operating frequency of the generator and the connection nym to the output gate electrode, installed in the outlet section of the apparatus just prior to the retarding electrode.

In this device, there is an additional possibility of high-frequency acceleration of the modulated density of the ion flux in the output section of the device, that is, in the interval between the output control and slow-down electrodes, which are affected by the maximum amplitude of the RF voltage of the generator. This voltage is synchronized in phase with the phase of ionic bunches formed in the input section of the device due to the modulation of ions by a low-amplitude sinusoidal signal acting on the first accelerating gap between the accelerating and input control electrodes. Due to the attenuator, it is possible to change the amplitude of the RF voltage at the first accelerating gap and, therefore, to smoothly adjust the traction force.

One of the disadvantages of the prototype is the low efficiency of the process of grouping ions into clots. This is due to the fact that the ion velocity modulation is carried out by a harmonic sinusoidal signal of one frequency F ₀ . Therefore, only ions located in the region of the half-period of the modulating high-frequency voltage (T ₁ = π) fall into the bunches, while ions do not fall into the bunches in the remaining half-periods.

In addition, ion clusters with a purely sinusoidal form of modulating RF voltage have a significant extent. Therefore, in the output section of the device, where ions arrive in the negative phase of the accelerating RF voltage, also having a sinusoidal shape, only the middle part of the bunch is accelerated to the maximum, and the beginning and end of this bunch acquire much less energy. As a result, the average velocity of the ion flux at the engine outlet decreases. The full efficiency of the device with high-frequency acceleration in the prototype does not exceed 50%.

In addition, in the presence of a large amplitude of an alternating RF voltage between the electrodes, the effect of dynamic “defocusing” of ions can occur, which, in the presence of RF modulation, can change the trajectory of motion and fall on the IOS electrodes, causing their erosion and destruction.

The technical problem of the invention is the need to achieve in the new device a higher and continuously adjustable speed of the ion stream, which provides an increase in traction and its adjustment in a wide range. In addition, the problem of the invention is the need to increase the durability of the device by reducing erosion and the likelihood of destruction of the IOS electrodes.

To solve the problems posed, a device for creating an adjustable traction force in an electric ion engine containing a gas discharge chamber ending with a screen electrode, a multi-beam ion-optical system (IOS), consisting of a series of plane electrodes with gaps connected in series with gaps connected to constant sources accelerating and braking voltage, a high-frequency oscillation generator having two high-frequency communication lines, one of which (input) includes an input attenuator and is connected via an input coil of an input parallel resonant circuit tuned to the operating frequency of the generator F ₀ and connected to the accelerating and input control electrodes multipath ILE installed in the input device section, and the second (output) frequency line includes a phase shifter and connected via coil output connection to an output parallel-resonant circuit, also tuned to the working frequency of the generator F _0, and an output coupled to a control electrode installed m in the output section of the apparatus immediately before the retarding electrode; introduced additional, sequentially alternating, control and focusing electrodes with span holes symmetrically separated from each other by shielding electrodes; moreover, the additional control electrodes located in the input section of the device are connected to two additional parallel oscillatory circuits, tuned, respectively, to two operating frequencies equal to twice (F ₂ = 2F ₀ ) and triple (F ₃ = 3F ₀ ) the frequencies of the high-frequency oscillation generator, connected to these circuits through two additional communication lines, in each of which are included frequency-matching frequency multipliers, adjustable phase shifters, attenuators, as well as additional communication loops; in addition, the first control electrode in the group of electrodes located in the output section of the device is connected to an additional output parallel oscillatory circuit, tuned, respectively, to the operating frequency equal to the tripled (F ₃ = 3F ₀ ) frequency of the high-frequency oscillator associated with this circuit through a third additional communication line containing, corresponding in frequency, a power amplifier, a phase shifter and a communication loop; in addition, the second control electrode in the group of electrodes located in the output section of the device is connected to the output control electrode, and all focusing electrodes located in the input and output sections of the device are electrically connected by a common wire to the input accelerating electrode. Moreover, the radius of the passage holes in the control and shielding electrodes and the ratio of the amplitudes of the RF voltage on the parallel resonant circuits located in the input and output sections of the device are selected from the following ratios:

where: a is the radius of the span holes in the control and shielding electrodes,

β = V _i / s is the relative velocity of the ion flux;

c is the speed of light;

λ ₁ = c / F ₀ is the working wavelength of the generator of high-frequency oscillations;

U _{1 (I)} - the amplitude of the RF voltage at the input parallel resonant circuit having a resonant frequency equal to the frequency of the generator of high-frequency oscillations F ₀ ;

U _{2 (I)} - the amplitude of the RF voltage at the additional input parallel oscillatory circuit tuned to double the operating frequency (F ₂ = 2F ₀ );

U _{3 (I)} - the amplitude of the RF voltage at the additional input parallel oscillatory circuit tuned to triple the operating frequency (F ₃ = 3F ₀ );

U _{3 (out)} - the amplitude of the RF voltage at the additional output parallel oscillatory circuit tuned to triple the operating frequency (F ₃ = 3F ₀ ).

The inventive device is illustrated using FIG. 1 ... 4, in which are presented: in FIG. 1 is a diagram of an electric ion engine; in FIG. 2 - coupling coefficients for a grouper operating at three multiple frequencies; in FIG. 3 - non-sinusoidal form of RF modulating voltage, acting in the input (grouping) section of the device, obtained by adding the signals of the main, double and triple frequencies; in FIG. 4 - non-sinusoidal form of the RF accelerating voltage acting in the output (accelerator) section of the device, obtained by adding the signals of the fundamental and triple frequencies. Positions 1 ... 46 in FIG. marked:

1 - gas discharge chamber,

2 - screen electrode;

3 - holes for the passage of ion beams made in flat electrodes;

4 - source of constant accelerating voltage;

5 - source of constant braking voltage;

6 - generator of high-frequency oscillations;

7 - input high-frequency communication line;

8 - input attenuator;

9 - input connection loop;

10 - input parallel resonant circuit tuned to the fundamental frequency F ₀ ;

11 - input accelerating electrode;

12 - input control electrode;

13 - input section of the device;

14 - output high-frequency communication line, designed to operate at the fundamental frequency;

15 - output phase shifter designed to operate at the fundamental frequency;

16 - a loop of communication with the input parallel resonant circuit of the fundamental frequency;

17 - output parallel resonant circuit tuned to the fundamental frequency F ₀ ;

18 - output control electrode;

19 - output section of the device;

20 - retarding electrode;

21 - additional control electrodes located in the input section of the device;

22 - focusing electrodes located in the input and output sections of the device;

23 - shielding electrodes having earth potential;

24 - additional input parallel oscillatory circuit tuned to double the operating frequency (F ₂ = 2F ₀ );

25 - additional input parallel oscillatory circuit tuned to triple the operating frequency (F ₃ = 3F ₀ );

26 - additional input communication line, designed to operate at a frequency of F ₂ = 2F ₀ ;

27 - additional input communication line, designed to operate at a frequency of F ₃ = 3F ₀ ;

28 - frequency multiplier with a multiplication factor K = F ₂ / F ₀ = 2;

29 - frequency multiplier with a multiplication factor K = F ₃ / F ₀ = 3;

30 - an additional adjustable phase shifter designed to operate at a frequency of F ₂ = 2F ₀ ;

31 - an additional adjustable phase shifter designed to operate at a frequency of F ₃ = 3F ₀ ;

32 - an additional adjustable attenuator designed to operate at a frequency of F ₂ = 2F ₀ ;

33 - an additional adjustable attenuator designed to operate at a frequency of F ₃ = 3F ₀ ;

34 - an additional loop of communication with an additional input parallel oscillatory circuit tuned to double the operating frequency (F ₂ = 2F ₀ );

35 - an additional loop of communication with an additional input parallel oscillatory circuit tuned to triple the operating frequency (F3 = 3F ₀ );

36 - the first control electrode in the group of electrodes located in the output section of the device;

37 - additional output parallel oscillatory circuit tuned to triple the operating frequency (F ₃ = 3F ₀ );

38 - additional output communication line, designed to operate at a frequency of F ₃ = 3F ₀ ;

39 - additional power amplifier designed to operate at a frequency of F ₃ = 3F ₀ ;

40 - additional phase shifter designed to operate at a frequency of F ₃ = 3F ₀ ;

41 - an additional round of communication with an additional output parallel oscillatory circuit tuned to triple the operating frequency (F ₃ = 3F ₀ )

42 - the second control electrode in the group of electrodes located in the output section of the device

43 - common electrical wire;

44 - converter;

45 - an additional power amplifier operating at the fundamental frequency;

46 - power source converter.

The inventive device for creating an adjustable traction force in an electric ion engine contains a gas discharge chamber 1 ending with a screen electrode 2, after which there is a series of consecutively mounted flat electrodes with span holes 3, forming a multi-beam ion-optical system (IOS). These electrodes are connected to sources of constant accelerating 4, and braking voltage 5. The device also includes a high-frequency oscillation generator 6 having an input and output high-frequency communication lines. The input high-frequency communication line 7 includes an attenuator 8 and is connected via an input communication coil 9 to an input parallel resonant circuit 10. This oscillatory circuit is tuned to the operating frequency of the generator F ₀ and is connected to the input accelerating 11 and input control 12 electrodes of the multipath IOS installed in the input section of the device 13. The second high-frequency communication line 14 includes an output phase shifter designed to operate at the fundamental frequency F ₀ . It is connected using the output coupling loop 16 with the output parallel resonant circuit 17, also tuned to the operating frequency of the generator F ₀ . This oscillating circuit is connected to the output control electrode 18 installed in the output section 19 of the device immediately before the slowdown electrode 20.

To solve the problems posed earlier, namely, to achieve in the new device a higher and smoothly adjustable speed of the ion stream in the accelerating system, with a reduced, compared to the prototype, value of the constant accelerating voltage, as well as in order to achieve greater device durability, in the IOS introduced additional, sequentially alternating, control and focusing electrodes with span holes.

Moreover, two additional control electrodes 21 located in the input section are separated from the focusing electrodes 22 using shielding electrodes 23, which are under the ground potential. In addition, these additional control electrodes are connected, respectively, with two additional parallel oscillatory circuits. In this case, the additional input parallel oscillatory circuit 24 is tuned to double the operating frequency (F ₂ = 2F ₀ ), and the additional input parallel oscillatory circuit 25 is tuned to triple the operating frequency (F ₃ = 3F ₀ ).

To connect these oscillatory circuits with a generator of high-frequency oscillations, two additional communication lines are introduced into the proposed device, respectively: an additional input communication line 26, designed to operate at a frequency of F ₂ = 2F ₀ and an additional input communication line 27, designed to operate at a frequency of F ₃ = 3F ₀ . In these lines, respectively, are located: a frequency multiplier 28 with a multiplication factor K ₂ = F ₂ / F ₀ = 2, a frequency multiplier 29 with a multiplication factor K ₃ = F ₃ / F ₀ = 3, adjustable additional phase shifters 30 and 31, attenuators 32 and 33, as well as additional turns of communication 34 and 35.

In addition, the first control electrode 36 located in the output section of the device is connected to an additional output parallel oscillating circuit 37, tuned, respectively, to triple the operating frequency (F ₃ = 3F ₀ ). To excite this oscillating circuit, an additional output line is introduced into the device high-frequency communication 38 containing a power amplifier 39, an additional phase shifter 40 and an additional round of communication 41.

The second control electrode 42 located in the output section of the device is connected to the output control electrode. All focusing electrodes, both in the input section and in the output sections of the device, are located in the gaps between the two shielding electrodes and are electrically connected by a common wire 43 to the input focusing electrode. The optimal operating modes of the device are selected from the above ratios (1 ... 4).

The device also includes a converter 44, designed to produce a quasi-neutral flow of charged particles, an additional power amplifier 45 operating at the fundamental frequency, and a power supply to the converter 46.

A device for creating an adjustable traction in an electric rocket engine works as follows. The gas discharge chamber is filled with a working gas, for example, xenon (Xe) with an atomic mass of 131.3 amu After initiating a gas discharge, for example, using microwave energy, the ions are removed from the gas discharge chamber using the first two IOS electrodes (screen -2 and input accelerating electrode-11).

For example, a potential of 27.25 kV is supplied to the electrode 2, and a potential of +25 kV is supplied to the electrode 11. At this stage of acceleration, the ions acquire a speed of 57.470 (km / s).

Further, the final acceleration of the multipath ion flux by a constant electric field occurs in the gap between the electrode 11 and the shield electrode 23, which is at zero potential. Under the action of a large accelerating potential difference, the ions enter the first double high-frequency (HF) gap formed by two shielding electrodes 23 and an input control electrode.

Further, ion beams pass through the holes in the first group of oppositely charged electrodes forming the first single lens. The focusing electrodes located in the center of this lens are positively charged relative to the shielding electrodes. Passing the central region of the first single lens, the ion beams expand until they enter the second double HF gap formed by two shield electrodes 23 and the first additional control electrode. In the region of this gap, the beams narrow, i.e., they focus.

Similarly, periodic movement of the rays and their focusing is carried out with the further passage of ion beams through a system of sequentially alternating control and focusing electrodes, both in the input and output sections of the device. In this case, alternating electrodes forming double-gap resonators and focusing electrodes in these sections form a single electrostatic periodic focusing system.

To supply the corresponding positive potential to the focusing electrodes, a separate power source is used. However, to simplify the engine power system, it is advisable to use the focus mode with the potential of the focusing electrode equal to the potential of the input accelerating electrode, connecting them with a common electric wire. To eliminate current subsidence on the focusing electrodes, the diameter of the holes in them is chosen slightly larger than the diameter of the holes in the control and shielding electrodes.

All IOS electrodes are spaced apart from each other, eliminating the possibility of electrical breakdown. Since the electric potentials of the electrodes of single lenses at their input and output are the same, the speed of the jet stream at the initial stage of acceleration by a constant electric field for this example is 200 (km / s).

A small increase in speed (for the above example, up to 210 (km / h)), the ions get at the output of the device, passing through the holes in the slowdown electrode 20, which is at a negative potential relative to the potential of the shielding electrode.

At the output of the device there is a hollow cathode — converter 44. Gas is supplied to the cathode. After applying the accelerating voltage from the power source 46, electrons are formed in the hollow cathode 44, which neutralize positively charged ions forming a quasi-neutral plasma jet stream at the output of the device. The small potential jump available at the output creates the conditions for the rupture of the beam plasma, preventing the return of electron back flows to the working volume of the engine.

Further, the regulation of the magnitude of the thrust in the proposed device is carried out due to their additional acceleration in a strong high-frequency electric field, the value of which is smoothly changed. For this, a small part (5 ... 10%) of the power of the RF generator 6 is supplied through the communication line 7, the attenuator 8 and the communication coil 9 to excite the resonant oscillatory circuit tuned to the fundamental frequency F ₀ .

This frequency, as well as the radius of the aperture a, is selected from the condition determined by relation (1), known from the theory of klystron (Yu.A. Katsman, Questions of the theory of multi-cavity klystrons. Svyazizdat Publishing House, 1958 - 316 s). It determines the choice of the maximum permissible maximum values of the passage angles along the radius of the passage channel for frequency F, at which the efficiency of the interaction of ions with the rf field is not small. For the above example, with U ₀ = 27.25 kV, β = 0.000667, you can choose λ ₁ = 12 m, then F ₀ = 25 MHz, F ₂ = 50 MHz, F ₃ = 75 MHz, a = 0.4 mm.

At the same time, part of the RF power is supplied to two additional input communication lines 26 and 27, where, using frequency multipliers 28 and 29, the signal frequency is converted to the frequency F ₂ = 2F ₀ and to the frequency F ₃ = 3F ₀ . The amplitude and phase of the signals in these lines are controlled using additional phase shifters 30 and 31, as well as attenuators 32 and 33, according to formulas (2) - (3).

After the passage of these devices, the signals of double and triple frequencies using the corresponding coils of communication excite the input parallel oscillatory circuit 24, which is tuned to double the operating frequency (F ₂ = 2F ₀ ). Ions passing through the first double HF gap with an antiphase voltage U _{1 (input)} will receive modulation in speed, which then goes to the density modulation of ions in the section of their motion in the drift region (the range of the inhibitory potential of a single lens).

Similar processes of high-speed modulation and the process of clot formation will occur in the following two-gap interaction areas, on which modulating voltages U _{2 (input)} , U _{3 (input)} will act. The geometric dimensions of the double gaps (the length of the gap d, the length of the control electrode L and the distance between the centers of the gaps S _in = d + L are chosen, as well as in the klystron (see Yu.A. Katsman, Questions of the theory of multi-cavity klystrons. Svyazizdat Publishing House, 1958 - 316 pp.) In such a way as to ensure high interaction efficiency (coupling coefficient M _{k of} ions with the HF field) simultaneously for all three (k = 1,2,3) double gaps (see Fig. 2).

For example, for the above example (k = 1,2,3; β = 0.000667; λ ₁ = 12 m; λ ₂ = 6 m; λ ₃ = 4 m; d ₁ = d ₂ = d ₃ = 1.25 mm ; а = 0.4 mm from equation (5), we find that for optimal lengths of the control electrodes (drift pipes L ₁ = L ₃ = 2.5 mm L ₂ = 4.5 mm), the coupling coefficients for all frequencies are in the range of values M ₁ = 0.918, M ₂ = 0.79, M ₃ = 0.56, providing high efficiency high-speed modulation.

From FIG. 3 it can be seen that in the input section of the device, which is a grouper of ions, the total RF modulating voltage U _Σ (ωt) in shape is close to the ideal (sawtooth) shape. The efficiency of nonlinear velocity modulation can be determined by evaluating the dimensionless duration T _{3 of the} total modulating voltage

In the prototype, from the period of HF oscillations, only half of all ions ϑ = 50% are collected in clots. In the case of modulation with three signals, the efficiency of nonlinear velocity modulation is

RF acceleration of ionic bunches is carried out in the output section, the interaction space in which is formed by three consecutive double high-frequency gaps formed between the ends of the control electrodes 36, 42, 18 and the shield electrodes 23. To accelerate ions, most of the power of the RF generator 6 using the high-frequency output line Communication 14 through a communication loop 41 is fed to the output parallel resonant circuit 17, tuned to the fundamental frequency F ₀ .

Next, this signal is supplied to the second control electrode 42 located in the output section of the device and connected to the output control electrode 18. To adjust the phase and amplitude of the RF voltage U _{1 (output)} for the main frequency signal, an additional power amplifier 45 and output phase shifter 15.

At the same time, the treble frequency signal (F ₃ = 3F ₀ ) is supplied to the double RF gap, the central electrode of which is the first control electrode 36 connected to the additional parallel output oscillating circuit 37. The RF signal is fed to this circuit via communication line 38 through the frequency multiplier 29 F ₃ = 3F ₀ .

The phase of the signals in this line is controlled using an additional phase shifter 40 so that the total RF voltage acting in the acceleration region is phase-synchronized with the phase of ionic bunches generated in the input section of the device due to high-speed modulation and grouping of ions by a non-sinusoidal sinusoidal signal. Due to the RF power amplifiers, 45 and 39 are selected, according to expressions (3-4), the amplitudes of the RF voltage for the signals of the main U _{1 (output)} and triple U _{3 (output)} frequencies for the accelerating gap. As a result, the shape of the total accelerating RF voltage will have an extended flat top (Fig. 4).

Therefore, in the output section of the device, where the ion bunches come in the negative phase of the accelerating RF voltage, not only the middle part of the bunches, but also their beginning and end are accelerated as much as possible. Since the velocities in the two accelerating double gaps add up, we can approximately take the total coupling coefficient equal to M _s ≈2⋅M _l K _u , where K _u ≈0.9 is a coefficient depending on the shape of the non-sinusoidal voltage (Fig. 4).

Provided that the relative amplitude of the accelerating voltage is U _Σ / U ₀ ≈1, the maximum change in the relative velocity of ions V _i (and hence the traction force) at the exit of the accelerating section will be ± 40%

For the example considered above, the ion velocity can be changed in the range of values of V _i = 210 ± 83 km / s. As a result of synchronous interaction with a large amplitude high-frequency field (U _Σ / U ₀ ≈1), ions can be accelerated to a speed of about 300 (km / s), which is 1.4 times faster than the modern four-grid ion engine Dual-Stage (DS4G) ( see pcnews.ru/.../dual-stage-ds4g-esa-10-210-smart-orson-sutherland-roger-walker-10319).

Instead of xenon (Xe), argon (Ar) can be used as the working gas. It is also an inert gas, but, unlike xenon, has a large ionization energy with a lower atomic mass.

Claims (15)

1. A device for creating an adjustable traction force in an electric ion engine, comprising a gas discharge chamber terminating in a screen electrode, a multi-beam ion-optical system (IOS), consisting of a series of plane electrodes with span openings connected in series with gaps connected to sources of constant accelerating and braking voltage generator of high-frequency oscillations having two high-frequency communication lines, one of which (input) includes an input attenuator and is connected with one coil connection with the input parallel resonant circuit tuned to the oscillator operating frequency F ₀ and connected to the accelerating and input control electrodes multipath ILE installed in the input device section, and the second (output) frequency line includes a phase shifter and is connected via an output coil communication with the output parallel resonant circuit, also tuned to the operating frequency of the generator F ₀ and connected to the output control electrode installed in the output section of the device is not directly in front of the retarding electrode; characterized in that the structure of the IOS includes additional, sequentially alternating, control and focusing electrodes with span openings symmetrically separated from each other by shielding electrodes; moreover, the additional control electrodes located in the input section of the device are connected to two additional parallel oscillatory circuits, tuned, respectively, to two operating frequencies equal to twice (F ₂ = 2F ₀ ) and triple (F ₃ = 3F ₀ ) the frequencies of the high-frequency oscillation generator, connected to these circuits through two additional communication lines, each of which includes frequency multipliers, adjustable phase shifters, attenuators, and also additional communication loops; in addition, the first control electrode in the group of electrodes located in the output section of the device is connected to an additional output parallel oscillatory circuit, tuned, respectively, to the operating frequency equal to the tripled (F ₃ = 3F ₀ ) frequency of the high-frequency oscillator associated with this circuit through a third additional communication line containing a frequency-appropriate power amplifier, phase shifter and communication loop; in addition, the second control electrode in the group of electrodes located in the output section of the device is connected to the output control electrode, and all focusing electrodes located in the input and output sections of the device are electrically connected by a common wire to the input accelerating electrode. 2. A device for creating an adjustable traction force in an electric ion engine according to claim 1, characterized in that the radius of the span holes in the control and shielding electrodes and the ratio of the amplitudes of the RF voltage on the parallel resonant circuits located in the input and output sections of the device are selected from the following relations : a = (0.06 ÷ 0.08) βλ ₁ , U _{2 (input)} = (0.45 ÷ 0.5) U _{1 (input)} ; U _{3 (in)} = (0.18 ÷ 0.2) U _{1 (in)} ; U _{3 (out)} = (0.1 ÷ 0.125) U _{1 (out)} ; where: a is the radius of the span holes in the control and shielding electrodes, β = V _i / s is the relative velocity of the ion flux; c is the speed of light; λ ₁ = c / F ₀ is the working wavelength of the generator of high-frequency oscillations; U _{1 (I)} - the amplitude of the RF voltage at the input parallel resonant circuit having a resonant frequency equal to the frequency of the generator of high-frequency oscillations F ₀ ; U _{2 (I)} - the amplitude of the RF voltage at the additional input parallel oscillatory circuit tuned to double the operating frequency (F ₂ = 2F ₀ ); U _{3 (I)} - the amplitude of the RF voltage at the additional input parallel oscillatory circuit tuned to triple the operating frequency (F ₃ = 3F ₀ ); U _{3 (out)} - the amplitude of the RF voltage at the additional output parallel oscillatory circuit tuned to triple the operating frequency (F ₃ = 3F ₀ ).

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