CN210401500U - Plasma current measuring device of Tokamak device based on Faraday effect - Google Patents
Plasma current measuring device of Tokamak device based on Faraday effect Download PDFInfo
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- CN210401500U CN210401500U CN201920857112.7U CN201920857112U CN210401500U CN 210401500 U CN210401500 U CN 210401500U CN 201920857112 U CN201920857112 U CN 201920857112U CN 210401500 U CN210401500 U CN 210401500U
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- optical fiber
- tokamak
- wave plate
- sensing
- optic fibre
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Abstract
The utility model discloses a plasma current measuring device of tokamak device based on Faraday effect, including installing optic fibre sensing ring in the vacuum chamber of tokamak device and being located the optical signal modulation system and the computer of the outdoor side of vacuum chamber of tokamak device, optic fibre sensing ring including quarter fiber wave plate, sensing optic fibre and speculum, optic fibre wave plate and speculum fix at the interior wall of tokamak vacuum chamber, sensing optic fibre extremely wind the round and will be located the terminal speculum of sensing optic fibre and the closed optic fibre wave plate of the other end in order to form closed sensing ring along the vacuum chamber wall of tokamak device; the optical fiber wave plate is connected with the optical signal modulation system through a polarization maintaining optical fiber, and the optical signal modulation system is connected with the computer through a signal wire. The utility model discloses can be to plasma current's long-time high accuracy measurement.
Description
Technical Field
The utility model relates to an electric current measurement technical field especially relates to a plasma electric current measuring device of tokamak device based on faraday effect.
Background
In a tokamak device, plasma hoop current is one of the most basic parameters for a tokamak discharge operation. Currently used in tokamak devices for measuring plasma current are rocco coils and their associated integrator systems. The plasma current is obtained after the differential signal of the current change measured by the Rogowski coil is subjected to integration processing by an integrator. Because the output of the integrator has time drift, the rocco coil and the matching integrator system thereof can not accurately measure the current for a long time in principle, and therefore a device which does not depend on the integrator and can accurately measure the plasma current for a long time is needed.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a plasma current measuring device of tokamak device based on faraday effect in order to compensate prior art's defect exactly.
The utility model discloses a realize through following technical scheme:
a plasma current measuring device of a Tokamak device based on a Faraday effect comprises an optical fiber sensing ring arranged in a vacuum chamber of the Tokamak device, an optical signal modulation system and a computer, wherein the optical signal modulation system is positioned on the outer side of the vacuum chamber of the Tokamak device; the optical fiber wave plate is connected with the optical signal modulation system through a polarization maintaining optical fiber, and the optical signal modulation system is connected with the computer through a signal wire.
The optical signal modulation system comprises a laser, a polarizer, a lithium niobate optical phase modulator and a photoelectric detector, wherein the output end of the laser and the input end of the photoelectric detector are both connected with one end of the polarizer, the other end of the polarizer is connected with the lithium niobate optical phase modulator, the lithium niobate optical phase modulator is connected with the optical fiber wave plate through a polarization maintaining optical fiber, and the output end of the photoelectric detector is connected with a computer.
The polarization maintaining fiber is led into a vacuum chamber of the Tokamak device from the outer side through a wall-penetrating flange.
And the high-birefringence polarization maintaining optical fiber is adopted to transmit the optical signal on the premise of ensuring the polarization state of the light.
The phase modulator modulates the optical phase to make the sensor always work in the best working state.
When the plasma current passes through the surface surrounded by the closed fiber current measuring instrument sensing ring, according to the Faraday effect, the induced magnetic field generated by the plasma current can enable two beams of circularly polarized light (left circularly polarized light and right circularly polarized light) transmitted in the sensing fiber to generate phase difference, and the phase difference can be obtained by the ampere loop theorem, and the magnitude of the phase difference is in direct proportion to the magnitude of the plasma current.
Wherein theta is the phase difference of two beams of circularly polarized light, V is the Walde coefficient of the optical fiber material, L is the sensing optical fiber loop path, and I is the plasma current. The direct measurement of the plasma current can be realized by measuring the phase difference between two beams of circularly polarized light.
The utility model has the advantages that: the utility model provides a can be to plasma current's long-time high accuracy measuring device, the installation is maintained conveniently, and occupation space is little, can lay sensing optical fiber according to the installation site environment in a flexible way, does benefit to and installs in the inside narrow and small space of tokamak device.
Drawings
Fig. 1 is a schematic diagram of the optical fiber sensing ring structure of the present invention.
Fig. 2 is a block diagram of the working principle of the present invention.
Detailed Description
As shown in fig. 1 and 2, a plasma current measuring device of a tokamak device based on faraday effect comprises an optical fiber sensing ring arranged in a vacuum chamber 1 of the tokamak device, an optical signal modulation system positioned outside the vacuum chamber of the tokamak device and a computer 2, wherein the optical fiber sensing ring comprises a quarter optical fiber wave plate 3, a sensing optical fiber 4 and a reflecting mirror 5, the optical fiber wave plate 3 and the reflecting mirror 5 are fixed on the inner wall of the tokamak vacuum chamber 1, the sensing optical fiber 4 winds a circle along the wall of the vacuum chamber 1 of the tokamak device in a polar direction and closes the reflecting mirror 5 positioned at the tail end of the sensing optical fiber with the optical fiber wave plate 3 at the other end to form a closed sensing ring; the optical fiber wave plate 3 is connected with the optical signal modulation system through a polarization maintaining optical fiber, and the optical signal modulation system is connected with the computer 2 through a signal wire.
The optical signal modulation system comprises a laser 6, a polarizer 7, a lithium niobate optical phase modulator 8 and a photoelectric detector 9, wherein the output end of the laser 6 and the input end of the photoelectric detector 9 are connected with one end of the polarizer 7, the other end of the polarizer 7 is connected with the lithium niobate optical phase modulator 8, the lithium niobate optical phase modulator 8 is connected with the optical fiber wave plate 3 through a polarization maintaining optical fiber, and the output end of the photoelectric detector 9 is connected with the computer 2.
The polarization maintaining fiber is led into a vacuum chamber 1 of the Tokamak device from the outside through a wall-through flange 10.
Unpolarized light with a wavelength of 1310nm emitted by a laser source is converted into linearly polarized light after passing through an optical fiber polarizer, and the linearly polarized light is divided into two beams of orthogonal linearly polarized light at a 45-degree welding angle between a polarizer tail fiber and an input optical fiber of a phase modulator. The phase modulator performs feedback control on the phase difference between the two beams of light according to the measurement result, so that the sensor always works in the optimal working state. And the polarized light signal between the phase modulator and the optical fiber wave plate is transmitted by using the polarization-maintaining optical fiber. The fiber quarter-wave plate converts two beams of orthogonal linear polarized light transmitted in the forward direction into left-handed and right-handed circularly polarized light, the two beams of circularly polarized light are transmitted in the sensing fiber and generate a phase difference theta due to the Faraday effect, the two beams of circularly polarized light are reflected by an emitter at the tail end of the sensing fiber and then return to the quarter-wave plate along the sensing fiber, and the phase difference of the two beams of light is changed into 2 theta due to the Faraday effect in the process. The two reflected circularly polarized lights are converted by the wave plate and then changed into linearly polarized lights, and the linearly polarized lights are subjected to secondary modulation by the phase modulator and then interfered at the polarizer. And finally, the optical signal enters a photoelectric detector, and the photoelectric detector converts the optical signal into an electric signal and sends the electric signal to digital signal processing equipment.
Claims (3)
1. A plasma current measuring device of a Tokamak device based on Faraday effect is characterized in that: the optical fiber sensing ring comprises a quarter optical fiber wave plate, a sensing optical fiber and a reflector, wherein the quarter optical fiber wave plate, the sensing optical fiber and the reflector are fixed on the inner wall of the tokamak vacuum chamber; the optical fiber wave plate is connected with the optical signal modulation system through a polarization maintaining optical fiber, and the optical signal modulation system is connected with the computer through a signal wire.
2. A faraday-effect-based apparatus for measuring plasma current of a tokamak apparatus according to claim 1, wherein: the optical signal modulation system comprises a laser, a polarizer, a lithium niobate optical phase modulator and a photoelectric detector, wherein the output end of the laser and the input end of the photoelectric detector are both connected with one end of the polarizer, the other end of the polarizer is connected with the lithium niobate optical phase modulator, the lithium niobate optical phase modulator is connected with the optical fiber wave plate through a polarization maintaining optical fiber, and the output end of the photoelectric detector is connected with a computer.
3. A faraday-effect-based apparatus for measuring plasma current of a tokamak apparatus according to claim 2, wherein: the polarization maintaining fiber is led into a vacuum chamber of the Tokamak device from the outer side through a wall-penetrating flange.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920857112.7U CN210401500U (en) | 2019-06-10 | 2019-06-10 | Plasma current measuring device of Tokamak device based on Faraday effect |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201920857112.7U CN210401500U (en) | 2019-06-10 | 2019-06-10 | Plasma current measuring device of Tokamak device based on Faraday effect |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN210401500U true CN210401500U (en) | 2020-04-24 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201920857112.7U Active CN210401500U (en) | 2019-06-10 | 2019-06-10 | Plasma current measuring device of Tokamak device based on Faraday effect |
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| CN (1) | CN210401500U (en) |
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2019
- 2019-06-10 CN CN201920857112.7U patent/CN210401500U/en active Active
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