FI91100B - Collective ion accelerator propulsion device - Google Patents

Description

91100

COLLECTIVE ION ACCELERATOR THRUST

The invention relates mainly to an electric propulsion device suitable for spacecraft and aircraft and to its power supply. The generation of thrust in space is based on Newton's third law, F = ma, where m is the mass to be transported out and a is its acceleration.

Carrying a large mass greatly limits the spacecraft's performance and distance, as evidenced by the law of motion retention applicable to all types of rockets or the like Mr * vr = Mp * vp, where the ship's momentum is on the left side of the equation and the propellant's momentum is on the right side. Thus, if a high velocity vp is obtained for the propellant mass Mp, then less propellant is needed to develop the momentum of a given vessel. With chemical rocket engines, the release rates of the propellant are of the order of 4 ... 5 km / s. and with advanced ion granules up to 1000 km / s.

On the other hand, the high discharge rate and thrust of an ion motor mean a high power requirement and but not necessarily a high energy if the motor operates on the thrust principle. The high electrical power demand of an advanced ion engine can be met by a nuclear reactor or a closed plasma MHD generator.

In many previously disclosed ion motor inventions, such as the following patents: EP 0132065, PCT WO 88/08488, DE 2052014, DE 3728011 and US 3956666, the acceleration of ions is based on a so-called conventional ion motor, in which ions are directly accelerated by a relatively low electric field strength. - 100 kV, which is limited by space charge and the effective ion current I remains small (mA class) and the thrust F <1 N. (F = 2 UI / vp). Figure 1.

Such a low-power motor can be used mainly for satellite orbit repairs, where the need for thrust is in the order of hundreds of mN, (e.g. UK-10 and UK-25, which are Kaufman-type ion motors).

For these two reasons, I have invented a new method to generate large thrust with a small electronic methods ajoainesyötöllä, involving also the required power of the plasma source enclosed MHD generator-rotor.

My invention is based on a collective ion accelerator used in nuclear physics, with which the ion mass can be accelerated to very high velocities (approx. 0.01 c) by utilizing a large electric field emission (approx. which is needed, for example, when a ship rises from the surface of the planet. Figure 3. In principle, the required large thrust forces can be developed if sufficient electrical power is available.

With a collective ion accelerator, high-current ion pulses with an energy of a few MeV / core and peak currents of 1 ... 100 kA can be generated. The discharged particles can be ionized atoms, molecules, dust, charged colloidal particles, or liquid droplets.

Such a collective accelerator can be used as a high-current ion source and ion engine in spacecraft, airplanes, boats, ships, cars, etc., as well as e.g. plasma as an ion source of a magnetohydrodynamic (MHD-) generator.

This type of vehicle is very environmentally friendly.

To achieve this, my invention is characterized by what is apparent from claim 1.

Figure 1 is a simplified drawing of a conventional ion source constrained by space charge and breakdown voltage VB.

P is the plasma region, f is the cathode, 2 is the anode, I is the ion beam and Va is the anode potential.

Figure 2 shows the dependence of the anode potential on the z-axis coordinate in Figure 1.

Figure 3 is a simplified description of a collective ion accelerator where 1 is a cathode, 2. is an anode, I is a relativistic electron beam, IREB, P is the plasma region generated by IREB passing through a migratory tube 2 filled with an injected gas cloud. VQ

is the potential of the cathode with respect to the anode.

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Figure 4 shows the dependence of the anode potential on the z-axis coordinate in Figure 3. E is the electric field strength. The negative potential potential (dashed line) moves with the ion bundle and acts as an accelerating electrode or virtual cathode for the positive ions. Figure 5 shows one possible application of the invention: a propulsion device for spacecraft or the like.

Figure 6 is a simplified diagram of a high voltage pulse generator serving as a high power power source for an IREB diode and an ion beam, where T is a GTO or equivalent switch, D is an energy recovery diode, C is a capacitor, L is an inductance and M is a double resonant pulse .

The collective ion accelerator is based on a cold cathode tube, where a very high instantaneous DC voltage between the cathode and the anode makes the anode positive for the cathode. The cathode is formed by a very sharp spike or tube or a set of them. This was done in order of obtaining a very high electric field strength between the cathode and the anode, in the order of 1 MV / mm. This results in electron emission from a cold cathode that follows the Fowler-Nodheim current density law.

This is called a field emission or a cold cathode emission.

If the distance between the anode and the cathode in the diode is 12 mm and the diameter of the anode aperture is 25 mm, an acceleration voltage of at least one million volts or 1 MV is required to achieve field emission, where the electron current can be on the order of 30 kA For this reason, we speak of an intense electron beam accelerated to a relativistic speed, or IREB for short. The required short-term acceleration voltage is best developed with a high-power light air core high-voltage pulse transformer or the like supplied by a switching device from a lower DC voltage obtained, for example, from a closed plasma MHD generator. When a gas jet is led to the inside of the anode inside the so-called vacuum hose near the anode opening, eg a gas jet, strong internal ionization of the gas occurs when the IREB hits the gas cloud and the charge cloud formed by electrons due to a strong electric field at a very high speed and develops a reaction force according to Newton's law.

This is called a collective ion accelerator, with the current of positive ions even in the kA order. With the thrust F of the ion motor depending on the jet power P and the speed vp: F = 2P / vp.

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Calculate, for example, the case that neon, Ne, with a relative atomic weight of n.20 and an ionic mass mi = 33.4 * 10 ~ 24 g is used as the ionizable propellant. if the ion beam current is 3 kA, then the number of ions is Ni = 1.87 * 1022 / s and the jet mass / s = ms = 0.62 g / s. If the acceleration voltage is U = 1MV, then the thrust is given by: F = (2 mp P) 1/2 * (2 * 6.2 * 10-2 * 3 * 109)! / 2 N = 1930 N Then the velocity of the jet of material is n. 0.01 c

When a high acceleration voltage is used, it is advantageous to use a propellant with the highest possible molecular weight, such as polyethylene, in order to achieve a high thrust.

In order for the spacecraft not to be electrically charged, the ion beam must be able to neutralize in a fairly short distance. If the distance between the acceleration electrodes is s, then the neutralization should take place at a distance of at least 2 s VT * after the acceleration electrode or the like. The virtual cathode should form before the 2s distance, creating an equilibrium state and equal amounts of positive and negative charges and forming a plasma region. This is achieved when the production of positive ions is sufficient to generate the maximum potential. In a collective accelerator, both the amount of propellant and the electron beam current can be regulated and an almost neutral jet of material can be achieved.

Referring to Figure 5, which shows a cross-section 4 and device arrangements of an embodiment of a collective propulsion device. In this ion motor, the ions are accelerated by the relativistic electron beam IREB.

The ion accelerator consists of a cylindrical vacuum chamber 4 made of stainless steel or the like and at the same time acting as an anode by means of which electrons are accelerated from a cold cathode 1. The right-hand part of the tube of the anode plate 2 is called a migratory tube. A circular opening 10 ... 25 mm in diameter is made in the anode plate welded to the migratory tube, in which a ring-shaped injection nozzle 6 for the propellant is mounted.

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The ionizable gas or liquid is led through this precision nozzle and solenoid valve 6a under the control of the thrust power processor 10 from the fuel tank 6b. The sensor systems required for the control and the associated electronics are not described here.

7 is a vacuum pump.

Due to the high current density of the cold cathode 1, it is made of tungsten or graphite, etc. and is placed in 6 ...

12 mm to the isolation distance from the anode and attached to the insulating end 3. A 0.5 ... 1MV DC pulse with a current value of tens of kA for a low load is supplied between the cathode and the anode cylinder by a high voltage pulse generator 5, schematically shown in Figure 6. From the DC high voltage source 15, through the primary capacitors 8, the switching device 9 and the cable 16.

11 is a reservoir of a high voltage pulse generator transformer and oil insulator 14, 12 is an end cap and 13 is an cathode end o-ring. The power of the thrust jet is adjusted by adjusting the supply of propellant and the parameters of the IREB generator according to the requirements of the thrust by the power processor 10.

Reference: C.L. Olson, U.Schumacher: Collective Ion Accelerator. 1979 Springer-Verlag

Claims (5)

An electrostatic thrust device for spacecraft, ships or the like, characterized in that it has a vacuum chamber (4) for accelerating an ionizable substance such that a very strong electric field (of the order of 10 ^ V / m) acts on the diode cathode and anode electrodes (1.2 ), where field emission from a cold cathode is generated, and where ion generation, acceleration, neutralization, and thrust are based on a collective ion accelerator, whereby ionization of the propellant can occur by a relativistic electron jet from a blown gas cloud or a propellant or laser beam. Propulsion device according to Claim 1, characterized in that the ion beam is neutralized inside the anode by means of a space charge cloud of electrons. Device according to Claim 1, characterized in that the large direct current potential required for accelerating the ion beam is obtained from a high-power (> MW) pulse generator in which the pulse duration, its frequency and the output voltage can be adjusted as desired. Device according to Claim 1, characterized in that the collective ion accelerator also acts as an ion vacuum pump. Device according to Claim 1, characterized in that it receives the electrical energy required from a closed magnetohydrodynamic (MHD) generator in which the collective ion accelerator acts as an ion source. li 7 91100