A light path calibration method suitable for high-speed compact ring plasma fast and accurate velocity measurement

Abstract

The present application relates to the technical field of optical path calibration, and more particularly to an optical path calibration method suitable for fast and accurate velocity measurement of high-speed compact toroid plasma. The technical scheme comprises the following steps: providing a stable optical path adjuster support, the support comprising a support base and a mounting fixed plate; directly abutting the bottom limiting structure of the support base with the flange surface of the side observation window interface on the compact toroid injector body, and rigidly locking the support base on the side observation window interface through fasteners with the compact toroid injector body as a rigid reference. The present application realizes high-precision, fast and stable calibration of the compact toroid plasma diagnostic optical path, provides reliable technical support for high-speed compact toroid plasma velocity and density measurement, and has the advantages of significant improvement of measurement accuracy, improvement of debugging efficiency and engineering applicability.

Description

Technical Field

[0001] This invention relates to the field of optical path calibration technology, and in particular to an optical path calibration method suitable for rapid and accurate velocity measurement of high-speed compact ring plasma. Background Technology

[0002] Compact torus (CT) injection technology is a key technique in magnetic confinement fusion devices and high-energy-density physics research, widely used in experimental scenarios such as plasma feeding, edge localized mode control, and current-driven processes. In CT injection experiments, accurate measurement of plasma velocity is crucial for understanding plasma dynamics, validating physical models, and optimizing injection parameters. A diagnostic system based on a fiber optic interferometer is the core tool for measuring plasma density and velocity parameters; its measurement accuracy directly depends on the long-term stability of the diagnostic optical path, the coaxiality of the optical paths on both sides of the accelerating region, and the consistency of the reference.

[0003] Currently, traditional optical path support structures used in compact ring injection diagnostic systems generally employ external brackets independent of the injector body. These brackets use their own structure as the mounting reference, rather than the compact ring injector body as a rigid reference. In practical applications, this design exposes the following technical drawbacks:

[0004] (1) Poor optical path stability and easy reference drift. Traditional independent brackets and injector bodies are separate structures, inevitably introducing assembly errors during installation. In addition, the brackets are susceptible to interference from external factors such as equipment operation vibration and ambient temperature changes, causing the optical path reference to shift. For fiber optic interferometer diagnostic systems, the coaxiality deviation of the optical paths on both sides of the acceleration zone and the reference drift will directly cause interference signal distortion and increased phase measurement error, and in severe cases, even lead to diagnostic failure. Experimental data show that under long-term pulse operation conditions, the optical path reference offset of traditional independent brackets can exceed 0.5 mm, and the corresponding diagnostic error for plasma density and velocity measurements can reach more than 10%, which is difficult to meet the requirements of high-precision physical experiments.

[0005] (2) The optical path debugging is inefficient and cumbersome. Traditional supports do not have precise limiting and guiding structures, and the coaxial calibration of the optical paths on both sides of the acceleration zone needs to be completed by repeatedly adjusting the position of the support and the attitude of the optical path adjuster. The debugging process is complicated and time-consuming. The coaxial calibration of a single optical path often takes several hours, and the debugging results are highly dependent on the operator's experience, making it difficult to guarantee parameter consistency. At the same time, the traditional support structure is bulky and has a low degree of modularity, making on-site disassembly, maintenance, and secondary calibration operations extremely inconvenient, and unable to meet the debugging needs of multiple batches and fast pace in compact ring injection experiments.

[0006] (3) Poor structural adaptability and low space utilization. The acceleration zone of the compact ring injector is the core experimental area, and the installation space is extremely small. Traditional independent supports are large in size and heavy in weight, which not only occupies a lot of effective installation space, but also has an adverse effect on the structural layout and vacuum sealing performance of the injector body. In addition, traditional supports are not optimized for the installation scenario of the double-sided observation windows in the acceleration zone, and cannot achieve symmetrical and precise positioning of the double-sided supports, which further increases the difficulty of adjusting the coaxiality of the optical path.

[0007] In summary, existing optical path support and calibration technologies for compact ring injection diagnostic systems have significant shortcomings in terms of optical path stability, debugging efficiency, and structural adaptability, making it difficult to meet the core requirements of high-speed compact ring plasma velocity measurement for rapid optical path calibration, accurate coaxiality, and long-term stability. Therefore, this application proposes an optical path calibration method suitable for rapid and accurate velocity measurement of high-speed compact ring plasma. Summary of the Invention

[0008] The purpose of this invention is to address the significant shortcomings of existing optical path support and calibration technologies in compact ring injection diagnostic systems in terms of optical path stability, debugging efficiency, and structural adaptability, which make it difficult to meet the core requirements of rapid optical path calibration, accurate coaxiality, and long-term stability for high-speed compact ring plasma velocity measurement. This invention proposes an optical path calibration method suitable for rapid and accurate velocity measurement of high-speed compact ring plasma.

[0009] The technical solution of this invention: An optical path calibration method suitable for rapid and accurate velocity measurement of high-speed compact ring plasma, comprising the following steps:

[0010] Step S1: Provide a stable optical path adjuster bracket, the bracket including a bracket base and a mounting plate;

[0011] Step S2: Directly attach the bottom limiting structure of the bracket base to the flange face of the side observation window interface on the compact ring injector body, and use the compact ring injector body as a rigid reference to rigidly lock the bracket base to the side observation window interface with fasteners.

[0012] Step S3: Fix the optical probe onto the standard optical mounting interface of the mounting plate;

[0013] Step S4: Install the mounting plate with the optical probe onto the outside of the locked bracket base;

[0014] Step S5: By adjusting the relative position of the arc-shaped limiting groove set on the bracket base and the connecting hole on the mounting plate, fine-tune the spatial attitude of the mounting plate until the optical path of the optical probe and the other optical probe on the opposite side of the acceleration zone of the compact ring injector achieve high-precision coaxial alignment.

[0015] Step S6: After completing the coaxial alignment, tighten the connector to fix the posture of the mounting plate and complete the optical path calibration.

[0016] Optionally, in step S2, the fitting gap between the bracket base and the side observation window interface is no greater than 0.1mm.

[0017] Optionally, in step S5, while fine-tuning the posture of the mounting plate by adjusting the arc-shaped limiting groove, the quality of the interference signal is monitored simultaneously, and step S6 is executed after the phase error meets the standard.

[0018] Optionally, the stabilized optical path adjuster bracket provided in step S1 has an integrated plate structure for both the bracket base and the mounting plate. The bracket base has a central optical path through hole for the optical path to pass through, and multiple arc-shaped limiting grooves are provided and distributed in a ring array around the outer periphery of the central optical path through hole.

[0019] Optionally, the method further includes step S7 after step S6: sequentially connecting the calibrated optical probe with the acquisition chassis, intermediate frequency equipment and control terminal to form a diagnostic optical path system.

[0020] Optionally, after step S7, step S8 is further included: sending a self-test command through the control terminal to check the coaxiality of the optical paths on both sides and the stability of signal transmission, and completing system initialization.

[0021] Optionally, in the method, the stable optical path adjuster bracket is symmetrically arranged at the side observation window interfaces on both sides of the acceleration zone of the compact ring injector, and uses the same compact ring injector body as a unified rigid reference, thereby forming a coaxial diagnostic optical path that runs through the acceleration zone of the injector.

[0022] Optionally, the fastener in step S2 is an internal hexagonal head screw, and the bottom of the bracket base is provided with a countersunk mounting hole to accommodate the head of the fastener to avoid structural interference.

[0023] Compared with the prior art, this application includes at least one of the following beneficial technical effects:

[0024] This invention uses the compact ring injector body as a rigid reference, replacing the traditional independent external support, thus eliminating the reference offset caused by assembly errors, equipment vibration, and environmental temperature drift at its source. Experiments show that after adopting this method, the optical path reference offset can be reduced from more than 0.5 mm in the traditional structure to less than 0.05 mm, and the plasma velocity and density diagnostic error can be reduced from more than 10% to less than 2%, effectively ensuring the measurement accuracy of the fiber optic interferometer.

[0025] The limiting structure at the bottom of the bracket base enables rapid and accurate initial positioning. Combined with the arc-shaped limiting groove and the mounting plate, there's no need to repeatedly adjust the overall position of the bracket; only minor adjustments to the mounting plate's orientation are required to complete the coaxial calibration of both optical paths. The calibration time for a single optical path coaxially is reduced from several hours using traditional methods to less than 15 minutes. Furthermore, the calibration results are independent of operator experience, exhibiting good consistency and perfectly meeting the demands of multi-batch, fast-paced calibration in compact ring injection experiments.

[0026] The bracket base and mounting plate adopt an integrated lightweight plate structure, symmetrically arranged on the observation window flanges on both sides of the acceleration zone of the compact ring injector. It occupies little space and does not interfere with the injector body structure and vacuum seal. At the same time, the two brackets use the same injector body as a reference, ensuring the consistency of the optical path reference on both sides and avoiding the additional deviations introduced by traditional brackets due to separate independent installation.

[0027] The rigid locking and limiting guide design ensures the stability of the optical path under long-term pulse operation, reducing the need for frequent calibration. The bracket is highly modular, easy to assemble and disassemble, and only requires loosening the arc-shaped limiting groove connector for fine-tuning during secondary calibration or maintenance, without disassembling the entire bracket, greatly improving its practicality in engineering.

[0028] In summary, this invention effectively solves the core problems of existing technologies, such as optical path reference drift, low debugging efficiency, poor spatial adaptability, and large measurement errors, through a bracket installation method with the injector body as a rigid reference, a rapid positioning method with limiting guidance, and a coordinated calibration method with precise fine-tuning of the arc groove. This invention achieves high-precision, rapid, and stable calibration of the compact ring plasma diagnostic optical path, providing reliable technical support for high-speed compact ring plasma velocity and density measurement, and exhibits significant improvements in measurement accuracy, debugging efficiency, and engineering applicability. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall connection of the diagnostic system;

[0030] Figure 2 This is a schematic diagram of the assembly structure of the transmitter / receiver bracket;

[0031] Figure 3 This is a schematic diagram of the support base.

[0032] Figure 4 This is a schematic diagram of the optical probe mounting plate.

[0034] Reference numerals in the attached diagram: 1. Compact ring plasma main unit acceleration zone; 2. Side observation window and lens interface; 3. Diagnostic equipment interface; 4. Intermediate frequency equipment; 5. Acquisition chassis; 6. Control terminal; 7. Support base; 8. Mounting plate; 9. Optical probe. Detailed Implementation

[0035] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0036] Example

[0037] This invention provides an optical path calibration method suitable for rapid and accurate velocity measurement of high-speed compact ring plasma. The method is based on a stable optical path adjuster bracket. By using the compact ring injector body as a rigid reference, and in conjunction with a limiting guide structure and an arc-shaped fine-tuning mechanism, it achieves rapid positioning, precise coaxial calibration, and rigid locking of the dual-sided diagnostic optical path, significantly improving the optical path calibration efficiency and long-term stability.

[0038] I. Overall Structure and Connections

[0039] like Figure 1 and Figure 2 As shown, the stable optical path adjuster bracket provided in this embodiment is assembled in the compact ring plasma diagnostic system, and is adapted to the side observation window interfaces 2 on both sides of the compact ring injector interface 1. Together with the acquisition chassis 5, intermediate frequency equipment 4, and control terminal 6, it forms a complete fiber optic interferometer diagnostic optical path. This diagnostic system is used for the precise measurement of the velocity and density of high-speed compact ring plasma.

[0040] like Figure 2 As shown, the stabilized optical path adjuster bracket mainly includes a bracket base 7, a mounting plate 8, and an optical probe 9. The bracket base 7 serves as the mounting base for the bracket, adapting to the flange structure of the side observation window interface 2 of the compact ring injector. It is precisely positioned and rigidly locked to the side observation window interface 2 via a bottom limiting structure. The mounting plate 8 is assembled on the outside of the bracket base 7 and has a standard optical mounting interface for supporting the optical probe 9. The optical probe 9 is fixedly installed at the standard mounting interface of the mounting plate 8, and its rear end connects to the acquisition housing 5, enabling collimated transmission and signal transmission of the diagnostic optical path.

[0041] The bracket is symmetrically arranged at the side observation window interface 2 on both sides of the compact ring injector interface 1, with the injector body as a unified rigid reference, thereby forming a coaxial diagnostic optical path that runs through the injector acceleration zone 1.

[0042] II. Structural Design of Key Components

[0043] like Figure 3As shown, the support base 7 adopts an integrated plate structure, made of high-strength aluminum alloy, combining structural rigidity and lightweight characteristics. A central optical path through-hole is provided in the center of the support base 7, which is coaxial with the center of the side observation window interface 2, ensuring unobstructed optical path. Four arc-shaped limiting grooves are provided on the support base 7, arranged in a circular array around the outer periphery of the central optical path through-hole. These arc-shaped limiting grooves are used to mate with the connection holes of the mounting plate 8, enabling quick clamping and fine-tuning of the mounting plate 8. Countersunk mounting holes are provided at the four corners of the bottom of the support base 7, used to rigidly lock the support base 7 to the flange face of the side observation window interface 2 using hexagonal head screws, thereby establishing a rigid connection based on the injector body. The countersunk mounting holes prevent fasteners from protruding and prevent structural interference.

[0044] The mating surfaces of the bracket base 7 and the side observation window interface 2 are precision machined flat surfaces, and the mating gap after assembly is no more than 0.1mm to ensure accurate positioning and reliable connection.

[0045] As a preferred embodiment, a sealing gasket can be added to the contact surface between the bracket base 7 and the observation window to prevent dust and reduce vibration, thereby further improving the stability of the optical path.

[0046] like Figure 4 As shown, the mounting plate 8 also adopts a one-piece lightweight plate structure with a coaxial standard optical mounting interface in the center for fixing the optical probe 9. The mounting plate 8 has connection holes corresponding to the arc-shaped limiting grooves of the support base 7. By adjusting the relative positions of the connection holes in the arc-shaped limiting grooves, the deflection angle and spatial attitude of the mounting plate 8 relative to the support base 7 can be finely adjusted, thereby achieving high-precision coaxial calibration of the dual optical paths. The four corners of the mounting plate 8 are chamfered to avoid installation interference and improve ease of operation.

[0047] The optical probe 9 is a general-purpose standard optical component, and an appropriate collimating lens can be selected as needed, eliminating the need for customization and ensuring high versatility. The optical probe 9 is rigidly connected to the mounting plate 8 to prevent loose installation from causing optical path misalignment and to ensure the stability of the diagnostic optical path.

[0048] III. Specific Steps of Optical Path Calibration Method

[0049] Based on the aforementioned stable optical path adjuster bracket, this embodiment provides an optical path calibration method suitable for rapid and accurate velocity measurement of high-speed compact ring plasma, comprising the following steps:

[0050] Step S1: Rigid reference installation of the bracket base. Directly align the bottom limiting structure of the bracket base 7 with the flange face of the side observation window interface 2 on the compact ring injector body. Using the compact ring injector body as a rigid reference, rigidly lock the bracket base 7 onto the side observation window interface 2 through the countersunk mounting holes using hexagonal head screws. Ensure that the fitting gap is no greater than 0.1mm and that the fasteners are not loose. At this point, the bracket base 7 and the injector body become one unit, fundamentally eliminating the assembly errors and vibration interference of traditional independent brackets.

[0051] Step S2: Pre-assembly of the optical probe and mounting plate. Securely mount the optical probe 9 onto the standard optical mounting interface of the mounting plate 8, ensuring a reliable connection. Then, install the mounting plate 8 with the optical probe 9 mounted onto the outside of the locked bracket base 7, initially aligning the connecting holes on the mounting plate 8 with the arc-shaped limiting grooves on the bracket base 7.

[0052] Step S3: Coarse positioning of the dual-sided optical path. At the symmetrical positions on both sides of the acceleration zone 1 of the compact ring injector, complete the installation of the dual-sided support base and mounting plate according to steps S1 to S2 above. The dual-sided supports use the same injector body as a rigid reference to ensure the consistency of the dual-sided installation reference.

[0053] Step S4: Fine-tuning of optical path attitude and coaxial calibration. The spatial attitude of the mounting plate 8 is fine-tuned by adjusting the relative position of the arc-shaped limiting groove on the support base 7 and the connecting hole on the mounting plate 8. Specifically, the operator, or with the assistance of the control terminal 6, moves the mounting plate 8 along the arc-shaped limiting groove to change the pointing angle of the optical probe 9. The quality of the interference signal or phase error index output by the fiber optic interferometer is monitored simultaneously. Repeated fine-tuning is performed until the optical paths of both optical probes 9 achieve high-precision coaxial alignment, the interference signal is stable, and the phase error meets diagnostic requirements.

[0054] Step S5: Attitude Locking. After completing the coaxial alignment, lock the connector to fix the attitude of the mounting plate 8 and complete the optical path calibration.

[0055] Step S6: System Connectivity and Self-Test. Connect the calibrated optical probe 9 to the acquisition chassis 5, intermediate frequency equipment 4, and control terminal 6 in sequence to form a diagnostic optical path system. Send a self-test command through the control terminal 6 to check the coaxiality of the two optical paths and the stability of signal transmission. After confirming that there are no abnormalities, complete the system initialization.

[0056] Step S7: Data Acquisition and Operation. The compact ring injector is activated to generate a high-speed plasma beam. The control terminal 6 issues an acquisition command, and the optical probe 9 acquires the diagnostic optical path signal in real time. After processing by the intermediate frequency equipment 4, the signal is transmitted to the acquisition chassis 5, achieving high-precision measurement of plasma velocity and density parameters.

[0057] Application example: In actual experimental operations, the optical path calibration method of the present invention can be performed according to the following preferred embodiment:

[0058] Preliminary preparation and overall inspection: Check the rigidity and locking status of the bracket base 7 and the side observation window interface 2, and confirm that the fitting gap is ≤0.1mm and the fasteners are not loose; verify that the mounting plate 8 and the arc-shaped limiting groove are properly aligned, the optical probe 9 is firmly installed and the fiber optic connection is reliable; check that the power supply and signal cable connections of the acquisition box 5, intermediate frequency equipment 4 and control terminal 6 are intact.

[0059] System power-on and initialization: Turn on the power to the control terminal 6, intermediate frequency device 4, and acquisition chassis 5 in sequence, and wait for the equipment to complete the self-test; the control terminal 6 enters the diagnostic system operation interface and completes the initialization configuration of optical path parameters, sampling frequency, etc.

[0060] Optical path reference self-test: Control terminal 6 sends a self-test command, starts optical probe 9 to output probe light, and checks that the optical paths on both sides are unobstructed and the central optical path is coaxial; confirms that the bracket is based on the injector body as a rigid reference and there is no offset or abnormal vibration.

[0061] Compact ring injector preheating standby: Start the compact ring injector to complete the establishment of vacuum environment and pulse power supply preheating, so that the injector enters the trigger standby state.

[0062] Precise optical path calibration: Fine-tune the posture of the mounting plate 8 by using the arc-shaped limiting groove to calibrate the coaxiality of the optical paths of the two optical probes 9; after the interference signal is stable and the phase error meets the standard, lock and fix the mounting plate 8.

[0063] Plasma beam triggering: Control terminal 6 sends a trigger signal to drive the compact ring injector to generate a stable plasma beam.

[0064] Start data acquisition: Control terminal 6 issues acquisition command to start high-density, continuous data acquisition and storage.

[0065] System operation monitoring: Real-time monitoring of optical path stability and signal quality, with automatic alarms in case of abnormalities; After the experiment, the beam is stopped, the acquisition is turned off, and the power is turned off to shut down.

[0066] It is worth noting that this invention uses the injector body as a rigid reference, eliminating assembly errors and vibration interference at the source. The optical path reference offset can be controlled within 0.05mm, and the diagnostic error is reduced to below 2%. The arc-shaped limiting groove design shortens the coaxial calibration time of the dual optical paths from several hours to less than 15 minutes, and does not rely on operator experience, ensuring good consistency. The integrated lightweight plate structure is symmetrically arranged in a small installation space without affecting the injector body structure or vacuum seal.

[0067] The above specific embodiments are merely several optional embodiments of the present invention. Based on the technical solutions of the present invention and the relevant teachings of the above embodiments, those skilled in the art can make various alternative improvements and combinations to the above specific embodiments.

Claims

1. An optical path calibration method suitable for rapid and accurate velocity measurement of high-speed compact ring plasma, characterized in that, Includes the following steps: Step S1: Provide a stable optical path adjuster bracket, the bracket including a bracket base (7) and a mounting plate (8). Step S2: Directly attach the bottom limiting structure of the bracket base (7) to the flange surface of the side observation window interface (2) on the compact ring injector body, and use the compact ring injector body as a rigid reference to rigidly lock the bracket base (7) to the side observation window interface (2) with fasteners. Step S3: Fix the optical probe (9) onto the standard optical mounting interface of the mounting plate (8); Step S4: Install the mounting plate (8) with the optical probe (9) onto the outside of the locked bracket base (7); Step S5: By adjusting the relative position of the arc-shaped limiting groove set on the bracket base (7) and the connecting hole on the mounting plate (8), fine-tune the spatial orientation of the mounting plate (8) until the optical path of the optical probe (9) and the other optical probe on the opposite side of the compact ring injector acceleration zone (1) achieve high-precision coaxial alignment. Step S6: After completing the coaxial alignment, tighten the connector to fix the posture of the mounting plate (8) and complete the optical path calibration.

2. The optical path calibration method for rapid and accurate velocity measurement of high-speed compact ring plasma according to claim 1, characterized in that, In step S2, the fitting gap between the bracket base (7) and the side observation window interface (2) is no greater than 0.1mm.

3. The optical path calibration method for rapid and accurate velocity measurement of high-speed compact ring plasma according to claim 1, characterized in that, In step S5, when the attitude of the mounting plate (8) is finely adjusted by adjusting the arc-shaped limiting groove, the quality of the interference signal is monitored simultaneously, and step S6 is executed after the phase error reaches the standard.

4. The optical path calibration method for rapid and accurate velocity measurement of high-speed compact ring plasma according to claim 1, characterized in that, The stable optical path adjuster bracket provided in step S1 has a bracket base (7) and a mounting plate (8) that are both integral plate structures. The bracket base (7) has a central optical path through hole for the optical path to pass through. Multiple arc-shaped limiting grooves are provided and are arranged in a ring array around the outer periphery of the central optical path through hole.

5. The optical path calibration method for rapid and accurate velocity measurement of high-speed compact ring plasma according to claim 1, characterized in that, The method further includes step S7 after step S6: connecting the calibrated optical probe (9) sequentially with the acquisition chassis (5), intermediate frequency equipment (4) and control terminal (6) to form a diagnostic optical path system.

6. The optical path calibration method for rapid and accurate velocity measurement of high-speed compact ring plasma according to claim 5, characterized in that, After step S7, step S8 is also included: sending a self-test command through the control terminal (6) to check the coaxiality of the optical paths on both sides and the stability of signal transmission, and to complete the system initialization.

7. The optical path calibration method for rapid and accurate velocity measurement of high-speed compact ring plasma according to claim 1, characterized in that, In the method, the stable optical path adjuster bracket is symmetrically arranged at the side observation window interface (2) on both sides of the acceleration zone (1) of the compact ring injector, and takes the same compact ring injector body as a unified rigid reference, thereby forming a coaxial diagnostic optical path that runs through the acceleration zone (1) of the injector.

8. The optical path calibration method for rapid and accurate velocity measurement of high-speed compact ring plasma according to claim 1, characterized in that, The fasteners in step S2 are internal hexagonal head screws, and the bottom of the bracket base (7) is provided with countersunk mounting holes to accommodate the head of the fasteners to avoid structural interference.

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