Method of determining nuclear fusion irradiation coordinates, device for determining nuclear fusion irradiation coordinates, and nuclear fusion device
09672944 ยท 2017-06-06
Assignee
Inventors
- Masakatsu Murakami (Suita, JP)
- Nobuhiko Sarukura (Suita, JP)
- Hiroshi Azechi (Suita, JP)
- Ryo Yasuhara (Hamamatsu, JP)
- Toshiyuki Kawashima (Hamamatsu, JP)
- Hirofumi Kan (Hamamatsu, JP)
Cpc classification
G21B1/23
PHYSICS
International classification
Abstract
An object of the present invention is to efficiently improve uniformity of energy lines to be irradiated. A method of determining nuclear fusion irradiation coordinates according to the present invention is a method of calculating irradiation coordinates when energy lines are irradiated onto a nuclear fusion target, and comprises an initial arrangement step S202 of virtually arranging electric charges Q.sub.i at initial coordinates of the number of irradiation coordinates N.sub.B on a spherical surface S.sub.0 set by using random numbers, a coordinate analysis step S203 of analyzing coordinates r.sub.i of the electric charges Q.sub.i in time series based on coulomb forces acting among the electric charges Q.sub.i by constraining the coordinates r.sub.i onto the spherical surface S.sub.0, potential evaluation steps S205 and S206 of determining a timing at which potential energies of the electric charges Q.sub.i were stabilized based on the coordinates r.sub.i, and an irradiation coordinate deriving step S207 of deriving coordinates r.sub.i at the timing at which potential energies were stabilized as irradiation coordinates of energy lines in a case where a nuclear fusion target is arranged at the center of the spherical surface S.sub.0.
Claims
1. A method of determining nuclear fusion irradiation coordinates for calculating irradiation coordinates of energy lines when the energy lines are irradiated onto nuclear fusion fuel, comprising: virtually arranging a predetermined number of electric charges at a predetermined number of initial coordinates on a spherical surface set by using random numbers by an information processing device; analyzing coordinates of the predetermined number of electric charges arranged at the initial coordinates in time series based on coulomb forces acting among the predetermined number of electric charges by constraining the coordinates onto the spherical surface by the information processing device; determining a timing at which potential energies of the predetermined number of electric charges were stabilized based on the coordinates analyzed in the coordinate analysis step by the information processing device; deriving coordinates of the predetermined number of electric charges at the timing determined in the potential evaluation step as irradiation coordinates of the energy lines in a case where nuclear fusion fuel is arranged at the center of the spherical surface by the information processing device; and arranging a predetermined number of energy line sources at positions within a nuclear fusion device corresponding to the irradiation coordinates when the nuclear fusion fuel is arranged at the center of the spherical surface.
2. The method of determining nuclear fusion irradiation coordinates according to claim 1, wherein in the step of determining the timing at which potential energies of the predetermined number of electric charges were stabilized, it is determined whether or not a temporal change of the sum of potential energies of the predetermined number of electric charges at the timing is not more than a predetermined value.
Description
BRIEF DESCRIPTION OF DRAWINGS
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DESCRIPTION OF EMBODIMENTS
(10) Hereinafter, a preferred embodiment of a method of determining nuclear fusion irradiation coordinates and a device for determining nuclear fusion irradiation coordinates according to the present invention will be described in detail with reference to the drawings. In the description of the drawings, portions identical to or equivalent to each other are designated by the same reference signs, and overlapping description will be omitted.
(11) First, a principle of inertial confinement fusion in a nuclear fusion device to which a method of determining nuclear fusion irradiation coordinates is applied is described with reference to
(12) In the central ignition system, as shown in
(13) In the fast ignition system, as shown in
(14) For realizing these ignition systems, a high compression density of fuel is required, and as a result, high implosion uniformity and laser light irradiation uniformity are demanded. The method of determining nuclear fusion irradiation coordinates and the device for determining nuclear fusion irradiation coordinates according to the present invention are for designing irradiation coordinates of energy lines in a nuclear fusion device to meet the described demand. Here, as energy lines to be irradiated for nuclear fusion ignition, laser light is used, and a D (deuterium)-T (tritiated hydrogen) reaction is assumed as a nuclear fusion reaction, and DT fuel is assumed as corresponding nuclear fusion fuel, however, the present invention is also applicable to other energy lines, nuclear fusion reactions, and fuels.
(15)
(16) As shown in
(17) The information processing device 30 includes a reading device 12 such as a floppy disk drive unit, a CD-ROM drive unit, and a DVD drive unit, a working memory (RAM) 14 in which an operating system is resident, a memory 16 that stores programs stored in a recording medium 10, a display unit 18 such as a display, a mouse 20 and a keyboard 22 as input devices, a communication device 24 for transmitting and receiving data, etc., and a CPU 26 for controlling executions of the programs. The information processing device 30 becomes accessible to a program stored in the recording medium 10 from the reading device 12 when the recording medium 10 is inserted into the reading device 12, and is allowed to operate as the device 1 for determining irradiation coordinates according to the present invention by this program.
(18) In detail, the functions realized by the respective sections shown in
(19) Hereinafter, functions of the respective sections of the device 1 for determining irradiation coordinates are described in detail.
(20) The input section 101 accepts an input of the number of irradiation coordinates of energy lines in a nuclear fusion device to be designed. Specifically, the input section 101 accepts an input of information on the number of irradiation coordinates using the mouse 20 and the keyboard 22, and stores the accepted data on the number of irradiation coordinates in the working memory 14, etc.
(21) The initial arrangement section 102 sets initial coordinates r0.sub.i (i=1, . . . , N.sub.B) of electric charges Q.sub.i (i=1, . . . , N.sub.B) as many as the number of irradiation coordinates N.sub.B based on the number of irradiation coordinates N.sub.B (N.sub.B is a positive integer) accepted by the input section 101. In detail, the initial arrangement section 102 includes a random number generation section 102a, and sets a spherical surface S.sub.0 centered on an origin O in a virtual space, and sets the initial coordinates r0.sub.i (i=1, . . . , N.sub.B) at random positions on the spherical surface S.sub.0 while referring to random numbers generated by the random number generation section 102a. Accordingly, the initial arrangement section 102 virtually arranges N.sub.B electric charges Q.sub.i at the positions represented by r0.sub.i on the spherical surface S.sub.0.
(22) The coordinate analysis section 103 analyzes coordinates of N.sub.B electric charges Q.sub.i whose initial coordinates r0.sub.i were set by the initial arrangement section 102 in time series. Specifically, the coordinate analysis section 103 calculates coulomb forces acting among the electric charges Q.sub.i when the charge amount of the electric charges Q.sub.i (i=1, . . . , N.sub.B) is set to q. Further, the coordinate analysis section 103 adds a condition that the electric charges Q.sub.i are constrained onto the spherical surface S.sub.0 (|r.sub.i|=1, i=1, . . . , N.sub.B) and temporally integrates N.sub.B systems of equations of motions relating to the coordinates r.sub.i (i=1, . . . , N.sub.B) of the electric charges Q by using the following equation (1):
(23)
to calculate all coordinates r.sub.i in time series. Here, the second term of the right side of the equation (1) is an artificial viscosity term for preventing micro-vibration of the solution.
(24) The potential evaluation section 104 determines a timing at which the potential energies of all electric charges Q.sub.i were stabilized based on the coordinates r.sub.i of the N.sub.B electric charges Q.sub.i analyzed by the coordinate analysis section 103. In detail, each time the coordinates r.sub.i are calculated by the coordinate analysis section 103, the potential evaluation section 104 calculates the sum E.sub.P of potential energies of the N.sub.B electric charges Q.sub.i according to the following equation (2):
(25)
Then, the potential evaluation section 104 determines whether the potential energies of the electric charges Q.sub.i have been stabilized by determining whether a temporal change of the sum E.sub.P is not more than a predetermined threshold Th.sub.P. For example, it is determined whether a difference between a sum E.sub.P based on the coordinates r.sub.i previously calculated and a sum E.sub.P based on coordinates r.sub.i calculated at this time is not more than the threshold Th.sub.P=10.sup.16.
(26) When the potential evaluation section 104 determines that the potential energies have been stabilized, the optimal coordinate determination section 105 identifies coordinates r.sub.i of the N.sub.B electric charges Q.sub.i at the stabilization timing. Then, the optimal coordinate determination section 105 derives these coordinates r.sub.i as coordinates corresponding to optimal irradiation coordinates of energy lines when the nuclear fusion target is arranged at the center of the spherical surface S.sub.0. Then, the optimal coordinate determination section 105 transmits the derived coordinates r.sub.i to the output section 106, and the output section 106 outputs the coordinates in a predetermined output format such as a table data format, etc., to the display 18 and the communication device 24.
(27) Next, a method of determining irradiation coordinates using the device 1 for determining irradiation coordinates is described with reference to
(28) First, the input section 101 of the device 1 for determining irradiation coordinates accepts an input of the number of irradiation coordinates N.sub.B of energy lines relating to the nuclear fusion device to be designed (Step S201). Next, the initial arrangement section 102 randomly sets initial coordinates r0.sub.i of the electric charges Q.sub.i (i=1, . . . , N.sub.B) as many as the number of irradiation coordinates N.sub.B on the spherical surface S.sub.0 by generating random numbers (Step S202).
(29) Thereafter, the coordinate analysis section 103 calculates coordinates r.sub.i of the electric charges Q.sub.i in time series by temporally integrating N systems of equations of motions in consideration of coulomb forces between the electric charges Q.sub.i (i=1, . . . , N.sub.B) (Step S203). Then, the coordinate analysis section 103 sets the time of coordinates r.sub.i to be calculated next as the time of the next step (Step S204).
(30) Further, the potential evaluation section 104 determines whether a temporal change of the sum E.sub.P of potential energies of all electric charges Q.sub.i is not more than the threshold Th.sub.P, and transmits the determination result to the optimal coordinate determination section 105 (Step S206).
(31) As a result, when a temporal change of the sum E.sub.P is not more than the threshold Th.sub.P (Step S206: YES), the optimal coordinate determination section 105 determines N.sub.B coordinates r.sub.i calculated at this timing as coordinates corresponding to the optimal irradiation coordinates of energy lines when the nuclear fusion target is arranged at the center of the spherical surface S.sub.0. At the same time, the output section 106 outputs information on the optimal irradiation coordinates to the display 18, etc., and the process is ended (Step S207).
(32) On the other hand, when a temporal change of the sum E.sub.P is more than the threshold Th.sub.P (Step S206: NO), the process is returned to Step S203 and the calculation of coordinates r.sub.i of the electric charges Q.sub.i relating to the time of the next step is repeated.
(33) Next, an example of a nuclear fusion device designed and manufactured by using the above-described method of determining irradiation coordinates is described.
(34) First, the optimal irradiation coordinates of energy lines derived by the device 1 for determining irradiation coordinates when the number of irradiation coordinates N.sub.B=4 is set are as shown in the following Table 1.
(35) TABLE-US-00001 TABLE 1 Pattern A Pattern B [] [] [] [] 83.353 151.59 43.643 286.3 21.243 150 51.307 63.369 96.647 291.14 72.996 180.54 96.647 111.14 43.643 16.296 83.353 331.59 128.69 109.36 96.647 21.143 128.69 289.36 69.92 124.29 107 172.19 110.08 48.444 72.996 270.54 83.353 241.59 136.36 66.435 158.76 112.74 136.36 246.43 158.76 202.74 72.996 0.54248 158.76 22.735 136.36 156.43 83.353 61.588 128.69 199.36 69.92 34.286 51.307 153.37 158.76 292.74 128.69 19.361 21.243 59.996 51.307 333.37 21.243 240 136.36 336.43 110.08 138.44 107 262.19 110.08 228.44 107 82.188 110.08 318.44 43.643 196.3 96.647 201.14 107 352.19 69.92 304.29 43.643 106.3 69.92 214.29 72.996 90.542 21.243 330 51.307 243.37
The coordinates derived here are represented by the polar coordinates (, ) on the virtual spherical surface S.sub.0.
(36) As shown in
(37) In detail, the laser light irradiation sources 203 are arranged so as to become capable of irradiating laser lights L.sub.1 that advance toward the center of the spherical target 202 by passing through virtual coordinate points P.sub.A and P.sub.B on the spherical surface S.sub.0 derived by the device 1 for determining irradiation coordinates. These coordinate points that determine the optimal coordinates of the laser light irradiation sources 203 are divided into two groups of coordinate patterns of 24 coordinate points P.sub.A and P.sub.B, and coordinate points P.sub.A corresponding to the pattern A in Table 1 form 6 squares each consisting of four points adjacent to each other, and coordinate points P.sub.B corresponding to the pattern B in Table 1 form eight equilateral triangles each consisting of three points adjacent to each other. As shown in
(38) Further, in Table 2, the optimal irradiation coordinates of energy lines derived by the device 1 for determining irradiation coordinates when the number of irradiation coordinates N.sub.B=24 is set are shown. In a nuclear fusion device to which the number of irradiation coordinates=24 of energy lines is applied, as in the case of the nuclear fusion device 201, laser light irradiation sources are provided at positions corresponding to 24 optimal irradiation coordinates when it is assumed that the spherical target is positioned at the center of the spherical surface S.sub.0.
(39) TABLE-US-00002 TABLE 2 [] [] 86.757 357.57 129.74 12.22 83.162 117.35 96.241 281.71 54.615 26.899 110.6 201.4 114.71 321.19 93.323 161.99 24.335 214.95 155.24 303.67 126.78 249.99 151.41 186.75 65.008 198.09 52.639 269.61 154.45 72.262 28.425 333.82 67.63 76.739 83.213 237.8 50.489 146.86 112.96 82.801 69.087 318.31 26.137 87.108 125.74 132.96 97.304 42.137
(40) Hereinafter, the optimal irradiation coordinates derived by the device 1 for determining irradiation coordinates shown in Tables 1 and 2 and the optimal irradiation coordinates derived by the device 1 for determining irradiation coordinates when the number of irradiation coordinates N.sub.B=72 is set are shown from another viewpoint.
(41) In the case of the number of irradiation coordinates N.sub.B=24, the coordinates (, ) obtained by applying the following equations:
.sub.i+4m+8k=(1).sup.m.sub.i+180 m
.sub.i+4m+8k=(1).sup.m.sub.i+95.6162 m+120 k
i=1, 2, 3, 4; m=0, 1; k=0, 1, 2
to the data shown in the following Table 3, are the optimal irradiation coordinates to be derived by the device 1 for determining irradiation coordinates.
(42) TABLE-US-00003 TABLE 3 N.sub.B = 24 N.sub.B = 48 N.sub.B = 72 i .sub.i [] .sub.i [] .sub.i [] .sub.i [] .sub.i[] .sub.i[] 1 26.24800 0.000000 21.24302 0.000000 24.49171 84.24238 2 52.56226 55.84264 43.64296 43.69981 41.30650 48.91327 3 67.23147 345.7672 51.30717 86.62623 49.87536 87.02248 4 84.37483 25.62150 69.91959 25.70934 63.43495 62.41641 5 72.99624 59.45306 67.52800 35.82484 6 83.35323 88.40802 77.90530 83.44693 7 87.27933 56.58353
(43) In the case of the number of irradiation coordinates N.sub.B=48, the coordinates (, ) obtained by applying the following equations:
.sub.i+6m+12k=(1).sup.m.sub.i+180 m
.sub.i+6m+12k=(1).sup.m.sub.i+37.2604 m+90 k
i=1, 2, . . . , 6; m=0, 1; k=0, 1, 2, 3
to the data shown in Table 3, are the optimal irradiation coordinates to be derived by the device 1 for determining irradiation coordinates.
(44) Further, in the case of the number of irradiation coordinates N.sub.B=72, the coordinates (, ) obtained by applying the following equations:
.sub.i+7m+14k=(1).sup.m.sub.i+180 m
.sub.i+7m+14k=(1).sup.m.sub.i+88.8328 m+72 k
i=1, 2, . . . , 7; m=0, 1; k=0, 1, 2, 3, 4
(.sub.71, .sub.71)=(0, 0), (.sub.72, .sub.72)=(180, 0)
to the data shown in Table 3, are the optimal irradiation coordinates to be derived by the device 1 for determining irradiation coordinates.
(45) With the above-described method of determining irradiation coordinates and device 1 for determining irradiation coordinates, by the information processing device 30, electric charges Q.sub.i are virtually arranged at the initial coordinates of the number of irradiation coordinates N.sub.B on the spherical surface S.sub.0, the coordinates r.sub.i of the electric charges Q.sub.i are analyzed in time series, and based on coordinates r.sub.i at the timing at which the sum E.sub.P of potential energies of the electric charges Q.sub.i was stabilized, irradiation coordinates of energy lines when the nuclear fusion target is arranged at the center of the spherical surface S.sub.0 are derived. With a nuclear fusion device manufactured by using this device 1 for determining irradiation coordinates, the uniformity in irradiation intensity of laser lights onto nuclear fusion fuel can be improved with a smaller number of coordinates of laser lights as compared with the conventional case.
(46)
(47) It was further confirmed that no laser beams were opposing each other with respect to the center of the spherical surface S.sub.0 when the number of irradiation coordinates N.sub.B was larger than 20 in the case of irradiation coordinates of laser lights obtained by the method of determining irradiation coordinates and the device 1 for determining irradiation coordinates according to the present embodiment. Therefore, deterioration in performance due to damage caused by opposing laser light sources can be avoided.
(48) Further, in the present embodiment, it is determined whether a temporal change of the sum E.sub.P of potential energies of the electric charges Q.sub.i is not more than the threshold Th.sub.P, so that irradiation coordinates with improved laser light irradiation uniformity can be efficiently derived within limited ranges of operation performance and operation time.
(49) With a nuclear fusion device manufactured by using the method of determining irradiation coordinates and the device 1 for determining irradiation coordinates, uniformity in irradiation intensity of energy lines onto a nuclear fusion target is improved, so that inertial confinement fusion can be stably caused.
(50) Here, preferably, it is determined in the potential evaluation step whether a temporal change of the sum of potential energies of a predetermined number of electric charges at the timing is not more than a predetermined value, or the potential evaluation means determines whether a temporal change of the sum of potential energies of the predetermined number of electric charges at the timing is not more than a predetermined value. In this case, irradiation coordinates with improved energy line irradiation uniformity can be efficiently derived.
INDUSTRIAL APPLICABILITY
(51) The present invention is applied to a method of determining nuclear fusion irradiation coordinates and a device for determining nuclear fusion irradiation coordinates that determine irradiation coordinates of energy lines onto nuclear fusion fuel, and a nuclear fusion device manufactured by using these method and device, and can efficiently improve uniformity of energy lines to be irradiated.
REFERENCE SIGNS LIST
(52) 1: Device for determining irradiation coordinates, 30: Information processing device, 102: Initial arrangement section (initial arrangement means), 103: Coordinate analysis section (coordinate analysis means), 104: Potential evaluation section (potential evaluation means), 105: Optimal coordinate determination section (irradiation coordinate deriving means), 201: Nuclear fusion device, 202: Spherical target (nuclear fusion target), 203: Laser light irradiation source (energy line source), S.sub.0: Spherical surface