The present application relates to a plasma vacuum chamber capable of carrying on nuclear fusions.
Nuclear fusion that involves collisions and reactions of Deuterium atoms with other Deuterium, Tritium, or Helium 3, to form Tritium, Helium 3, Helium 4 or/and neutrons or protons can generate large amount of energy. One attempted method to produce nuclear fusion is to form a plasma at adequate energy and adequate plasma density to cause enough nuclear reactions to achieve net energy gains. The confinement of plasma has been a major challenge to achieve net energy gain.
One major issue is the lack of electrodes in Tokomak types of reactors. Since the vacuum chamber walls are either grounded or floating electrically, a plasma cannot be generated inside the vacuum chamber. Instead, a plasma is induced by an external changing current, typically by the Inner Poloidal Electrical Coils in a Tokamak. When the current reaches a maximum value, new ions and electrons can no longer be generated. It is thus difficult to sustain stable plasma. Energy injection by neutral beams has low energy efficiency, the Deuterium and Tritium gas has to be ionized, accelerated, and neutralized to avoid bending of the ion beam by strong magnetic field inside Tokomak. Most ions in the ion beam are not neutralized and have to be wasted, resulting in low energy utilization.
Another major issue is the loss of ions and electrons to the vacuum walls, which drain energy from the plasma. Even if the magnetic fields are carefully designed to contain plasma, the randomized ion motions due to collisions make it hard to contain plasma by magnetic field alone. The thermal plasma motions are in every direction, only small portion of ions collides in head-on directions, which has the maximum relative energy to achieve nuclear fusion. Furthermore, the entire body of gas inside the vacuum chamber must be heated to high temperature, resulting in large convection heat loss to the wall. The heat loss due to radiation is also large due to direct radiation from the high-temperature plasma to cold vacuum chamber.
The present application discloses a nuclear fusion system that provides stable plasma at high energy efficiency. The disclosed Tokamak includes electrodes in its interior to supply energetic ions and maintain a stable plasma. The number of ions that reach the electrodes or vacuum chamber walls are reduced. The electrode can also act as high temperature shield to reduce the radiation heat loss of the plasmas.
In one general aspect, the present invention relates to a controlled nuclear fusion system that includes a vacuum chamber, an electrode cage shaped in a first closed-loop tube in the vacuum chamber, wherein the electrode cage comprises electrically conductive wires configured to confine ions and electrons in the electrode cage and a toroidal electromagnetic coil coiled around outside of the electrode cage and configured to produce a closed-loop magnetic flux in the electrode cage.
Implementations of the system may include one or more of the following. The controlled nuclear fusion system can further include an outer poloidal magnet and an inner poloidal magnet configured to produce a plasma in presence of the closed-loop magnetic flux in the vacuum chamber. The electrode cage can include an input and an output, wherein the input and the output are separated by a gap to reduce induction current by the inner poloidal magnets. The electrode cage is configured to be negatively biased relative to the vacuum chamber to form a potential surface to confine the ions. The electrode cage can be positively biased relative to the vacuum chamber to confine the electrons inside the electrode cage. The electrode cage can be electrically connected to the vacuum chamber. The electrode cage can be electrically isolated to the vacuum chamber. The electrode cage can be electrically biased relative to the vacuum chamber by an alternating voltage to trap ions and electrons in the electrode cage. The vacuum chamber can be shaped in a second closed-loop tube, wherein the second closed-loop tube of the vacuum chamber can be nested in the first closed-loop of the toroidal electromagnetic coil. The toroidal electromagnetic coil can be coiled around outer surfaces of the vacuum chamber. The toroidal electromagnetic coil can be inside the vacuum chamber. The electrode cage can include a plurality of looped electrodes positioned in a toroidal shape to form the first closed-loop tube. The looped electrodes in the electrode cage can include a superconducting material to form the closed loop magnetic flux. The electrode cage can be formed by a conducting coil that are positioned in a toroidal shape to form the first closed-loop tube. The electrode cage can be formed by a toroidal mesh of crisscrossed conducting wires and insulating wires. The electrode cage can be formed by a toroidal mesh of conducting wires.
Tokamak uses strong superconducting coil magnets to confine both ions and electron and use induction current from Inner Poloidal Magnet Coils to ionize and heat up plasma. To have net energy gain, enough energy must be put into the plasma and maintain the high temperature plasma for sufficient time. The challenges are energy loss due to ions and electrons hitting the vacuum chamber walls, radiation loss from the plasma to cold vacuum chamber walls, stability of plasma, and efficiency of injecting energy into plasma. The Tokamak lacks electrodes and relies on induction heating to generate plasma. When the induction current reaches its limit, the plasma collapse and the neutralized molecules can no longer be confined by magnetic fields and lose their energy. The present invention provides a continuous plasma source and a mean to provide energy to the plasma, reduces the energy losses due to plasma hitting chamber walls, and reduces radiation losses from the higher temperature plasma to the chamber walls.
A controlled nuclear fusion system is described below in conjunction with
Referring to
Referring to
In some embodiments, the bias voltage of the electrode cage can be rapidly switched to attract ions to the vacuum chamber walls 140 and then repel the ions before the ions reach the vacuum chamber walls 140 to reduce loss of ions. Electrons have much smaller mass and can move rapidly without magnetic field confinement, the strong magnetic field near the vacuum chamber walls 140 can significantly increase the path of electrons and the time it takes electrons to reach the walls 140. It is possible to have the right frequency of the bias voltage between electrode cage 150 and vacuum chamber walls 140 to trap both electrons and ions.
Engineering method such as placing insulators between vacuum chamber 140 and the electric coil 156 can further reduce ions that can reach the electric coil 156. The trapping of electrons 160 by the magnetic field 161 will reduce the loss of electrons to the tokamak vacuum chamber 140, ionize molecules in its path, and generate a stable plasma 162. The bias voltage on the electrode cage 150 reduces loss of ions to the walls of the vacuum chamber 140 and can generate new ions and electrons between the tokamak vacuum chamber 140 and the electrode cage 150 to sustain the plasma. The wires or tube cage can also have large current to induce plasma directly and input energy more efficiently. The acceleration of ions from outside the electric coil 156 into the cage is another way to inject large amount of energy into the plasma (
In some embodiments, the toroidal electromagnetic coils 130 can be located inside the tokamak vacuum chamber 140. The electrode cage 150 is inside the toroidal electromagnetic coil 130. In other words, the tokamak vacuum chamber 140, the toroidal electromagnetic coil 130, and the electrode cage 150 all have toroidal shapes and are nested inside each other like Russian dolls. This design has the benefit confining the plasma in the center portion of the tokamak vacuum chamber 140. This design enables the tokamak vacuum chamber 140 to have increased dimensions relative to the electrode cage 150 to further localize the plasma and reduce plasma loss at the walls of the tokamak vacuum chamber 140. Additionally, the toroidal electromagnetic coils 130 can be made of superconducting materials to increase magnetic strength.
In some embodiments, referring to
The electrode cage 205 or the electrode cage 150 (in
In some embodiments, the toroidal electromagnetic coils 130 can be located inside the tokamak vacuum chamber 140. The electrode cage 205 consists of looped electrode 200 are inside the toroidal electromagnetic coil 130. In other words, the tokamak vacuum chamber 140, the toroidal electromagnetic coil 130, and the electrode cage 205 are nested inside each other like Russian dolls. The electrode cage 205 and the toroidal electromagnetic coil 130 have toroidal shapes, but the outside vacuum chamber can have other shapes such as a cylindrical shape (shown in
It should be noted that although the tokamak vacuum chamber 140 can be inside or outside of the toroidal electromagnetic coil 130, the toroidal electromagnetic coil 130 is always coiled around outside of the electrode cage 205 as shown in
In some embodiments, the toroidal electromagnetic coils 130 can be inside or be part of some or all looped electrode 200. The outside surface of the looped electrode 200 can be electrically biased against the vacuum chamber 140, grounded, or floating.
In some embodiments, referring to
The above-described embodiments can be used together with magnetic field configurations and induction mechanism of various magnet coils in Tokamak. The region between the wire or tube cage and the vacuum chamber wall is very suitable for generating ions and electrons. The electrons are confined by closed-loop magnetic fields parallel to the wire or tube cage until the electrons ionize gas molecules. These positive ions are pulled into the wire or tube cage by the bias voltage between the wire or tube cage and vacuum chamber walls and provide a source of ions to stabilize plasma. The bias voltage also prevents most ions inside the cage from reaching the vacuum chamber walls. The strong magnetic field will reduce the number of electrons or reduce the energies of the electrons that reach the vacuum walls. In addition, in a thermalized plasma inside the Tokamak, the energy of each electron may be much less than that of ion, assuming the electron and ion have similar velocity, and the energy loss of the plasma is mainly due to ion losses to the vacuum chamber walls. By providing a very efficient plasma generation and stabilization mechanism, the present invention improves the plasma stability of the conventional Tokamak and adds another mean to input energy to the plasma. By having a much smaller physical surface on the wire or tube cage and by preventing ions from reaching vacuum chamber walls, the present invention reduces the loss of ions to vacuum chamber walls. The additional voltage will accelerate some electrons to the vacuum chamber walls, the strong magnetic fields and light mass of the electrons will confine the electrons much longer, causing the electrons to lose energy to the plasma and not adding significant total loss of the plasma energy to vacuum chamber walls.
The surface temperature of the wire or tubes can be significantly higher than the vacuum chamber surface, since the vacuum chamber wall temperature is limited due to maximum thermal expansion allowed, vacuum sealing requirement, and lack of vacuum isolation between vacuum chamber and the surrounding environment in air. The higher temperature wire or tube cage will act as a buffer to reduce the radiation heat loss of the plasma. Since the radiation heating is proportional to the 4th power of absolute temperature, an intermediate layer at temperature T between plasma and vacuum chamber wall at temperature Tw can reduce radiation loss by σ (T4−Tw4) A, where σ=5.67×10−8 J/s·m2·K4 is the Stefan-Boltzmann constant and A is the surface area of the intermediate area, assuming the emission coefficient is 1. If T=3000K, and Tw is 800K, the radiation loss is reduced by approximately 4.57MJ/s/m2, which is very significant. The heat radiation from the wire or tube cage to vacuum chamber walls is caused by the radiation and plasma heating of the hot plasma and does not increase the total energy loss.
In one implementation, referring to
The voltage and current on the electrical coil can be adjusted at various stages of the operation to avoid excess amount of heating and loss of plasma. There is no need to pass a current to generate a magnetic field in the wire or tube cage, if there is strong magnetic field present from the Toroidal coils in Tokamak, simplifying the power supplies requirement. The vacuum chamber can be biased, and the wire or tube cage can be near ground potential. In extreme case, the coils in present invention can have similar electrical potential as the vacuum chamber walls and away from the most intense region of the plasma in the Tokamak. The induction heating of plasma by an electrical coil inside the vacuum chamber reduces energy losses to the chamber wall and other type of conductors.
Referring to
In some embodiments, a plurality of looped electrodes in
Only a few examples and implementations are described. The electrode cage can be negatively biased against the vacuum chamber in most instances, the electrode cage may also be positively biased or not biased against the vacuum chamber and still form a plasma. The polarity and magnitude of the voltage bias of the electrode cage can be optimized for the maximum energy efficiency in each specific nuclear fusion system. The inner surfaces of vacuum chamber and the surfaces of electrode cage that face plasma can be partially or completely covered by insulators or other materials that can stand high temperature. Partially covered conductive surfaces can still form an electrical potential surface to inject energy or to prevent ions or electron loss. The self-bias voltage on insulator surfaces by plasma may also help plasma confinement. Plasma can be influenced by the electrical potential formed by the voltage underneath the insulators. Voltages on insulator surfaces can still be induced by radio frequency (RF) power underneath the insulators, even if the insulators completely cover the conductive surfaces. Other implementations, variations, modifications and enhancements to the described examples and implementations may be made without deviating from the spirit of the present invention.
Number | Date | Country | |
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63233265 | Aug 2021 | US |
Number | Date | Country | |
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Parent | 17819146 | Aug 2022 | US |
Child | 18772146 | US |