KR100312751B1 - Method and apparatus for amplifying magnetic field of magnetic fluid - Google Patents

Abstract

PURPOSE: A method and an apparatus for amplifying a magnetic field of a magnetic fluid are provided to amplify a magnetic field by changing density distribution within a magnetic fluid and using a cross-field diffusion method. CONSTITUTION: The first coil(20) is wound around a fluid path(10) in order to form a magnetic field on a magnetic fluid. The second coil(30) is formed nearly to an inner wall of the fluid path(10) in order to change density distribution of the magnetic fluid. The third coil(40) is formed nearly to the inner wall of the fluid path(10) in order to sense the amplified voltage. The first coil(20) is formed with a solenoid coil. The second and the third coils(30,40) provide an input portion and an output portion of the fluid path(10). The magnetic field is formed within the fluid path(10) by the first coil(20).

Description

Magnetic field amplification method and apparatus of magnetic fluid

The present invention relates to a magnetic field amplification method and apparatus capable of amplifying a magnetic field using density phenomena and transport phenomena of a fluid in a magnetic fluid container.

One of the major challenges yet to be solved in conventional magnetic fluid systems such as plasmas is the cause of magnetic field amplification often found in sunspots, galaxies or some fusion research devices. A representative example of the problem of magnetic field amplification is sunspot development. In 1919, Larmor proposed that the fluid motion of the plasma induces a magnetic field, so that the mechanical energy of the fluid can be converted into the energy of the magnetic field. This mechanism of converting the fluid's mechanical energy into magnetic field energy is called the dynamo mechanism. Although various mechanisms have been proposed for this magnetic field amplification phenomenon, the present invention applies a method using diffusion.

The key to the magnetic field amplification mechanism is, in short, how to transform the mechanical energy of a fluid to derive a large magnetic field from a small magnetic field. To this end, it is essential to overcome the antidynamo theorem to symmetric fluid motion demonstrated by Cowling. Existing ideas are nonlinear in the movement of fluids slightly out of symmetry, as has been promoted since the 1950s by Parker, Braginskii, Steenbeck, Krause and Moffet. The possibility of magnetic field amplification by combining with electromagnetic fields has been mainly studied. This average field theory approach, coupled with the observation that there is an irregular rotational movement in almost all of the celestial systems, constitutes the framework for almost all dynamo ideas, currently considered as the only coping solution to overcome the antithesis of cowling. .

In order for the magnetic field amplification mechanism to be established, the movement of the fluid passing through the magnetic field lines is required. In order to account for the observed magnetic field amplification, the velocity of this fluid need not be large at all. The difficulty of the dynamo theory is that the magnetic fluid and magnetic field lines move together due to the line-tying effect when the temperature of the magnetic fluid is high. Many previous researchers have believed that magnetic field coupling effects can be overcome by three-dimensional nonlinear effects, and in fact this is the only way to be considered. It is particularly noteworthy that the cross-field diffusion of the magnetic fluid indicates the movement of the magnetic fluid passing through the magnetic lines of force, satisfying the conditions for becoming a dynamo mechanism from the beginning. In addition, this cross field diffusion can be used to amplify a significant amount of magnetic field when the density distribution of the magnetic fluid is low.

However, while theoretically studying magnetic field amplification in magnetic fluids, especially in plasma, it has fallen short of directly generating or using magnetic field amplification.

An object of the present invention is to provide a magnetic field amplification method for changing the density distribution in a magnetic fluid and amplifying a magnetic field using cross-field diffusion.

Another object of the present invention is to provide a magnetic field amplification apparatus that changes the density distribution in a magnetic fluid and amplifies the magnetic field using cross-field diffusion.

1A is a schematic diagram of a magnetic field amplifier.

FIG. 1B is a graphical representation showing the cross sectional area of a fluid with radius within the magnetic fluid container. FIG.

Figure 2a is a graph showing the change in the model plasma density according to the radial distance of the plasma vessel.

Figure 2b is a graph showing the change of the magnetic field over time according to the radial distance of the plasma vessel.

<Explanation of symbols for the main parts of the drawings>

10 ... magnetic fluid reservoir, 20 ... solenoid coils

30 ... RF inputs, 40 ... magnetic field amplification outputs

According to an aspect of the present invention, there is provided a magnetic field amplification method for amplifying a magnetic field from a magnetic fluid, the method comprising: applying a voltage to a first coil wound around an outside of a passage through which the magnetic fluid flows; Changing a density distribution of the magnetic fluid by applying a high frequency voltage to a second coil installed in the magnetic fluid; And amplifying the changed density distribution of the magnetic fluid using a cross-field diffusion method.

The present invention provides a magnetic field amplification apparatus for amplifying a magnetic field from a magnetic fluid, to achieve the above technical problem, the magnetic fluid flow passage; A first coil wound around the exterior of the passage to apply a voltage to form a magnetic field in the magnetic fluid; A second coil installed in the magnetic fluid to apply a high frequency voltage to change the density distribution of the magnetic fluid; And a third coil installed in the magnetic fluid so as to sense the amplified voltage by using the cross-field diffusion method in the density distribution of the changed magnetic fluid.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

First, before describing the magnetic field amplification method and apparatus of the present invention, the magnetic field generation requirements will be briefly described.

Fluid velocity for magnetic field maintenance is generally very small. However, the fluid velocity must be perpendicular to the line of magnetic force. In the case of the ideal magnetic fluid (MHD), the fluid and the line of magnetic force move together. This phenomenon is called the frozen in-field effect or the line-tying effect. By this effect, no net magnetic flux can be induced in an ideal magnetic fluid.

Thus, very small fluid velocities are sufficient for magnetic field amplification in magnetic fluids. By the way, even the small movement of the fluid seems to be capable of generating a magnetic field, but in reality, no fluid movement can actually increase the magnetic flux due to the magnetic force line coupling effect. Resolving these contradictions is a requirement for any dynamo theory and makes the dynamo mechanism difficult.

In the case of ideal MHD, all fluid movements were accompanied by magnetic field lines, but surprisingly many such movements are virtually unnoticed. In the case of cross-field diffusion flows associated with transport phenomena, the definition states that the motion of the fluid is relative to the line of magnetic force. In general, diffuse flow is neglected in MHD technology because of its very small size. However, cross-field fluid motion may result in an increase in net magnetic flux since it exhibits fluid motion separate from the magnetic field lines and can break the magnetic field line coupling effect. In this case, there is no reason to be ignored in MHD. In this case, the question is whether this microfluidic flow can induce a large enough magnetic field to be physically important. Contrary to the general expectation that this effect is expected to be negligible, it can be shown that in some cases a significant amount of magnetic field can be induced.

Before looking more closely at the new magnetic field amplification mechanism according to the present invention, we first look at the contradictions hidden in the mean field theory. Conducting boundary conditions are often adopted for high-conductivity plasmas, where the net magnetic flux is irrelevant regardless of whether the fluid or magnetic field fluctuations are regular, irregular, linear, or nonlinear. It can be explained that flux cannot be increased as follows.

로 쓴다. B₀은 평형자기장,

는 요동 자기장이다. 일반화된 저항법칙 (Generalized Ohm's law)을 사용하여 반경 a를 갖는 원통단면에 대해 적분해보면Consider the following cylindrical plasma. Assuming that the magnetic field is only in the Z direction, B _z = B ₀ +

Write with B ₀ is the equilibrium magnetic field,

Is the oscillating magnetic field. Using the Generalized Ohm's law, integrating against a cylindrical section with radius a

[Equation 1]

The first term of Equation 1 disappears when the conductor boundary condition υ _z = 0 and b _γ = 0.

이므로 수학식 1은then,

Equation 1 is

Equation 2 below

[Equation 2]

Becomes

에 의해 항상 감소됨을 보여준다. 이 결과는 평균장 이론에도 적용되며, 만약 일반적으로 받아들여지는 도체 경계 조건이 적용된다면 평균장이론에서의 비대칭적 유체운동이 자기장 증폭을 가져올 수 없다는 결론을 암시한다. 그러나, 도체 경계 조건이 실상 일종의 근사치이고 플라즈마 경계에서 확산에 의해 다음의 수학식 3으로 표현되는 작은 유체의 움직임This result is the electrical resistance

It is always reduced by. This result also applies to mean field theory, suggesting that asymmetric fluid motion in mean field theory cannot lead to magnetic field amplification if generally accepted conductor boundary conditions are applied. However, the conductor boundary condition is actually an approximation, and the motion of a small fluid represented by the following equation 3 by diffusion at the plasma boundary.

[Equation 3]

If present, the first term in Equation 1 is finite and under certain conditions, the effect may be greater than the second term, which is a decay term. At this time, the magnitude of the magnetic flux (magnetic flux) to be amplified depends on the size of the diffusion coefficient.

로부터 이상 확산계수

까지, D_class<D<D_Bohm를 생각해 볼 수 있다. 여기서, k는 볼쯔만 상수(Boltzmann constant), e는 전하, T는 온도이다.Diffusion coefficient D is classical

Ideal diffusion coefficient from

So far, D _class <D <D _Bohm can be considered. Where k is the Boltzmann constant, e is the charge, and T is the temperature.

When the diffusion coefficient has a classical value, that is, in the case of D = D _class , the electromotive force (emf) induced by the diffusion flow is

[Equation 4]

를 사용하면 다음의 수학식 5와 같이 자기장 증폭률을 계산할 수 있다.Is obtained. This result suggests that, in the case of a positive density gradient, ie in the case of a hollow density profile, the motion of the fluid by classical diffusion can result in electrical resistive attenuation. For more than ohm transport, the first term in Equation 1 is much larger than the second term, allowing magnetic field amplification.

By using the magnetic field amplification rate can be calculated as shown in Equation 5 below.

[Equation 5]

In the case of typical sunspot parameters, B ≒ 1000gauss, n ≒ 10 ¹³ / cm3, L = 2a ~ 100km, thus the magnetic field amplification factor γ ≒ 3 × 10 ⁸ / sec ≒ 1 / month is obtained. This value is in good agreement with the observed growth rate of sunspots.

The results are numerically solved using the generalized law of resistance as follows. Model the sunspot as an infinite cylinder of radius a. Assume that the magnetic field is in the Z direction and that the plasma has a hollow density profile and n (r) gradually increases from the center to the interface. Since the equilibrium state satisfies P + B ² / 8π = const and the magnetic field inside the sunspot is much higher than the outside, it is assumed that the density of the plasma inside the sunspot is slightly low, so that the hollow density profile is formed. Will be.

The change in magnetic field over time is expressed by Equation 6 below.

[Equation 6]

이 된다.

Becomes

이 플라즈마의 확산계수의 대표적인 값으로 취해진다. 봄 이상 확산에 의한 유체의 속도 υ_DB∼D_Bohm/L 로써 약 0.6cm/sec이 된다. 이 값은 알펜속도(Alfven velocity )υ_A=7×10⁶cm²/sec 보다 엄청나게 작은 값이나 유체의 운동에서 확산에 의한 흐름을 무시하는 것은 이 예에서 이해할 수 있을 것이다. 더 나아가 고전적 확산계수가 사용되는 경우는

가 되어 유체의 속도는 10⁵정도 더 적어진다. 이에 대한 기술은 본 발명자의 논문 (Journal of the Korean Physical Society, Vol. 28, No. 1, February, 1995)에 개시되어 있다. 이 논문에서 수치적 적분을 수행하였다. 초기 자기장은 100gauss로 균일하다고 가정하고 4시간 스텝으로 800시간 까지 적분하였다. 이로써, 중심부에서 자기장이 수 킬로가우스까지 증폭된다는 것을 알 수 있다.Plasma parameters are taken about 4000 km from the solar surface. The magnetic field takes 100 gauss, density n = 7.5 × 10 ⁸ / cm ³ , T _e = 61 ev, T _e = T _j , and the plasma radius is 50 km. In this case, the resistance η is 4.7 × 10 ⁻¹⁶ sec. Due to the strong magnetic activity in the sun and the very high levels of electromagnetic fluctuations, the diffusion coefficient over spring is taken as the plasma diffusion coefficient. therefore,

It is taken as a typical value of the diffusion coefficient of this plasma. It is about 0.6cm / sec as the velocity υ _DB ~ D _Bohm / L of the fluid by diffusion over spring. This value is enormously smaller than the Alven velocity v _A = 7 × 10 ⁶ cm ² / sec, but it can be understood in this example to ignore the flow due to diffusion in the motion of the fluid. Furthermore, if classical diffusion coefficients are used

The velocity of the fluid becomes 10 ⁵ less. Techniques for this are disclosed in the present inventor's article (Journal of the Korean Physical Society, Vol. 28, No. 1, February, 1995). In this paper, numerical integration is performed. The initial magnetic field was integrated at up to 800 hours in 4 hour steps, assuming 100gauss uniformity. As a result, it can be seen that the magnetic field is amplified to several kilogausses at the center.

=6.1×10¹⁷sec, D_Bohm=3.13×10⁵cm²/sec, D_class=5.49×10cm²/sec 이 되고, υ_the=6×10⁸cm/sec, υ_thi=1.4×10⁷cm/sec 가 된다. 여기서 주목할 점은 봄(Bohm) 이상 확산계수와 관련된 유체의 속도 υ_DB7×10²cm/sec, 고전적 계수와 관련된 유체속도 υ_Dclass1.2×10^-1cm/sec 이 됨으로써, 앞에서 언급한 여타 플라즈마 속도에 비해 무시할만큼 작은 값들을 갖는다. 따라서, 많은 플라즈마 분석에서 확산의 영향이 무시되어 온 이유를 쉽게 알 수 있다.Here are some things to note: First, the magnetic field is amplified only when diffusion is described by the ideal coefficient. If the diffusion coefficient has a classical value, the magnetic field cannot be sufficiently amplified. Second, the magnetic field is not amplified unless the plasma density is hollow. If the density profile has an opposite sign gradient, the magnetic field is not amplified but rather reduced. The following example shows that the magnetic field induced by the plasma diffusion can play an important role in the plasma produced in the laboratory. For a laboratory plasma, take the following parameters: B = 4000 gauss, n = 5 × 10 ¹³ / cm ³ , T _A = 200 eV, T _e = T _i , plasma radius α is about 20 cm, in this case resistance

= 6.1 × 10 ¹⁷ sec, D _Bohm = 3.13 × 10 ⁵ cm ² / sec, D _class = 5.49 × 10 cm ² / sec, υ _the = 6 × 10 ⁸ cm / sec, υ _thi = 1.4 × 10 ⁷ cm / sec. It is important to note that the velocity of the fluid associated with the diffusion coefficient above the _{ohm is} ν _DB 7 × 10 ² cm / sec, and the fluid velocity associated with the classical coefficient υ _Dclass 1.2 × 10 ^-1 cm / sec, which means Have negligibly small values for speed. Thus, it is easy to see why the effects of diffusion have been ignored in many plasma analyses.

In order to show that a small fluid velocity due to diffusion can lead to sufficient magnetic field amplification at the MHD scale at small density gradients, a schematic diagram of the magnetic field amplification apparatus is shown in FIG.

In FIG. 1, the magnetic field amplification apparatus of the present invention is a magnetic field amplification apparatus for amplifying a magnetic field from a magnetic fluid. A first coil 20 wound around the second coil, a second coil 30 installed near an inner wall of the passage of the magnetic fluid to change the density distribution of the magnetic fluid by applying a high frequency voltage, and the density distribution of the changed magnetic fluid The third coil 40 is installed near the inner wall of the passage of the magnetic fluid to sense the amplified voltage using the cross-field diffusion method. The first coil 20 wound around the magnetic fluid passage 10 may be a solenoid coil, and the second and third coils 30 and 40 may have a circular shape so as to be perpendicular to the flow direction of the magnetic fluid. A coil wound and providing an input and an output to the outside of the fluid passage. As shown in FIG. 1B, the surface of the fluid flowing in the fluid passage 10 is distributed to have a lower density toward the center. In this configuration, the magnetic field is formed in the magnetic fluid passage 10 by the solenoid coil 20, and when a high frequency is applied through the second coil 20 to change the density of the magnetic fluid, An abnormal transport phenomenon of the fluid occurs, and this density change is magnetically amplified by the cross-field diffusion method to sense the magnetic flux change in the third coil 40 to implement the magnetic amplification method. The calculation result for n (χ) = 5 × 10 ¹³ (1 + χ / 2000) ^1/2 of FIG. 2A is shown in FIG. 2B. This change in density will be ignored in the experiment. Even with this small density change, we can see the observed magnetic field change on the MHD time scale of several milliseconds. According to this result, when the plasma transport phenomenon is non-classical, it means that a small density gradient can bring about a magnetic field change.

≒7.5×10⁷/cm³이 되어, 지수함수 증폭시간은 대략 마이크로초(micro second order)가 된다. 이 경우 자기 프로브를 사용하면, 전압 스파이크(voltage spike)를 감지할 수 있을 것이다.It is thought that this magnetic field amplification mechanism by plasma diffusion can be verified in the laboratory. This magnetic field amplification is possible when the hollow density profile and the anomalous transport occur simultaneously. Hollow density profiles are possible by exciting a high frequency (RF wave) near the wall to deliver a neutral gas to create a plasma. Golovato and Shohet (1978) obtain a hollow density profile in the Proto-Celo stellerator by exciting Alpenpa by keeping the Alpenpa's resonance layer near the wall. Showed that. In this experiment, the density of plasma increased about 2-3 times from the center to the resonance layer. In the case of the hollow density profile, the plasma is diffused inward, and the fluid flowing inward by the plasma diffusion may cause magnetic field amplification. For example, if the plasma parameters are B = 100 _gauss , n ≒ 10 ¹¹ / cm ³ , and radius a ≒ 20cm, the magnetic field amplification factor is

≒ 7.5 × 10 ⁷ / cm ³ , the exponential amplification time is approximately microsecond order. In this case, using a magnetic probe will be able to detect voltage spikes.

Recently, Ellingboe and Boswell (1996) have reported hollow density profiles in helicon plasma. They attached a 200 cm long, 90 cm diameter diffusion chamber to a 50 cm long, 18 cm diameter plasma source tube, and inserted a 13.56 MHz high frequency up to 2.6 kW, and their paper clearly shows the hollow density profile. The magnetic field amplification seems to be a bit evident in this experiment, but it is not yet distinguished from the amount due to the antenna current combined with the perturbation.

In the magnetic field amplification mechanism according to the present invention, hollow density profiles and abnormal transport phenomena are essential requirements. I think that the fact that alfalfa can cause anomalous transport can be useful in achieving this. In particle computer simulation studies, it has been known that the collective movement of plasmas to a far-field region greatly influences the transport of particles. These phenomena have been known to be due to electrostatic convective cells of frequency zero. When there is a fluctuation of the plasma, the mode of frequency 0 is purely attenuated, and it has been shown by theory and simulation since 1970 that electrostatic fields in this mode can cause abnormal transport to plasma particles. . The present invention has shown that this mode of frequency 0 may be a limiting factor for the Alpen waves, which means that abnormal transport may occur when the Alpen waves are at leisure.

It is also believed that Alpenpa can be usefully used to create hollow density profiles. The reason for this can be found in an experiment on Alfven wave excitation in a proto-cleo stealer in the late 1970s. Golovato and Shohet (1978) conducted alpen wave heating experiments in a proto-cleo stellarator, which was excited by a helical wave launcher surrounding the torus. At this time, it was found that the electron temperature and the ion temperature doubled, respectively. They found a hollow wave resonance at the theoretical prediction point, where plasma heating was so high that the plasma density was about six times higher than the central or edge regions, and a hollow density profile with a diameter of about 6 to 7 cm appeared. . In addition, it has been found that when Alpenpa is excited in the proto-cleo, it is proportional to the plasma density and frequency as in the case of plasma heating. In other words, the more efficiently the plasma is heated, the higher the plasma loss.

In the present invention, since plasma sealing is not important as in fusion research, the experimental results found in the proto-cleo, that is, the higher the intensity of the Alpenpa, the better the hollow density profile and the higher the transport phenomenon. Use it in reverse. In fact, in wave heating experiments, if the waves are excited near the plasma edges, it can be expected that some hollow density profile will be seen in any wave heating experiment because these waves ionize the central particles near the cylinder wall to produce a plasma. However, in the case of alfalfa, the maximum amplitude at the resonance point is obtained. Therefore, if the resonance point can be properly adjusted to create a hollow density profile of a suitable shape, it is possible to use anomalous transport inherent in alpenpa. Magnitude magnetic field amplification can be seen. In addition, it is thought that alfalfa is more efficient than an helicon mode in obtaining an ideal transport or a hollow density profile.

As described above, the magnetic field fluid amplification method and apparatus according to the present invention can be applied to a new field such as a continuous fusion device or a magnetic fluid generator (MHD generator), so that the industrial applicability is very high.

Claims (6)

In the magnetic field amplification method for amplifying a magnetic field from a magnetic fluid, Applying a voltage to the first coil wound around the outside of the passage through which the magnetic fluid flows; Changing a density distribution of the magnetic fluid by applying a high frequency voltage to a second coil installed at an inner wall of the magnetic fluid passage; And Amplifying the changed density distribution of the magnetic fluid using a cross-field diffusion method. The magnetic field amplification method of claim 1, wherein the high frequency voltage is an Alpen wave. 3. The apparatus of claim 2, further comprising a third coil installed near an inner wall of the passage through which the magnetic fluid flows to sense the intensity of the amplified magnetic field, and wound in a circle perpendicular to the flow direction of the magnetic fluid. Magnetic field amplification method characterized in that. A magnetic field amplification apparatus for amplifying a magnetic field from a magnetic fluid, A passage through which magnetic fluid flows; A first coil wound around the exterior of the passage to apply a voltage to form a magnetic field in the magnetic fluid; A second coil disposed near an inner wall of the passage through which the magnetic fluid flows so as to change a density distribution of the magnetic fluid by applying a high frequency voltage; And And a third coil installed near the inner wall of the passage of the magnetic fluid so as to sense the amplified voltage using the cross-field diffusion method of the changed density of the magnetic fluid. The magnetic field amplifying apparatus according to claim 4, wherein the second and third coils are wound in a circle perpendicular to the flow direction of the magnetic fluid and drawn out of the magnetic fluid passage. 6. The magnetic field amplifying apparatus according to claim 5, wherein the high frequency voltage is alpen wave.

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