Pilot channel electron density diagnosis system and method based on slit spectrum

Abstract

The invention relates to the technical field of high-voltage insulation prediction, in particular to a pilot channel electron density diagnosis system and method based on a slit spectrum, and the system comprises an impulse voltage generator, a high-voltage electrode, a condensing lens, a slit, a first collimating lens, a second collimating lens, a VPHG, a high-speed camera, an electro-optical converter, a photoelectric converter, an oscilloscope, and a computer. According to the invention, the electron density in the pilot channel is accurately obtained, the evolution characteristics of physical characteristic parameters in the pilot channel in the long-gap discharge process can be effectively described, and high-precision calculation of the electron density can be realized without measuring the temperature; compared with the prior art, the method has the advantages that the time resolution and the space resolution are improved, the high diagnosis precision is ensured, the monitoring capability of the electron density change in the pilot discharge channel is enhanced, the change of the electron density can be effectively monitored in time and space, and the physical mechanism and characteristics in the pilot discharge process can be deeply understood.

Description

Technical Field

[0001] The present invention relates to the technical field of high voltage insulation prediction, and in particular to a leading channel electron density diagnosis system and method based on slit spectrum. Background Art

[0002] The study of long air gap discharge is the basis of external insulation design and lightning protection design of high voltage power transmission and transformation projects. Leader discharge is the most critical discharge mode in the long gap discharge process. Accurately obtaining the microscopic physical parameters in the leader discharge channel, especially the evolution characteristics of electron density, is of great significance for a deep understanding of the physical mechanism of leader discharge, and helps to achieve the refined design of external insulation of power transmission and transformation projects, and provide a theoretical basis for lightning protection design. Although electron density is one of the most important physical parameters in the leader discharge channel, the existing technology has not yet provided an ideal measurement method. Since electron density is difficult to measure directly, the early probe method can infer the electron density in the plasma channel, but it is only applicable to scenarios with lower electron density. In recent years, laser Thomson scattering and interferometry technology have been used to measure electron density, but the measurement accuracy is still low.

[0003] At present, the Saha equation and Stark broadening method are mainly used to calculate electron density using emission spectra. The Saha equation requires that the discharge channel satisfies the local thermodynamic equilibrium (LTE) condition and assumes that the discharge channel is an optically thin layer. However, the temperature of the leading discharge channel is relatively high (1500-6000K) and does not meet the LTE condition. The difficulty in obtaining temperature limits the application of the Saha equation. In contrast, the Stark broadening method only needs to measure the full width at half maximum (FWHM) of the target spectral line. The electron density can be calculated through the broadening formula, which is independent of the temperature of the discharge channel. Therefore, it has a wider application potential. Although these existing methods have made some progress, they still face challenges in terms of accuracy and scope of application.

[0004] The purpose of the present invention is to provide a leader channel electron density diagnosis system and method based on slit spectroscopy, which can realize the spatiotemporal continuous diagnosis of the electron density in the leader discharge channel, and help to deepen the explanation of the development mechanism of long-gap leader discharge. Summary of the invention

[0005] The invention provides a leading channel electron density diagnosis system and method based on slit spectrum.

[0006] A pilot channel electron density diagnostic system based on slit spectrum includes an impulse voltage generator, a high voltage electrode, a focusing lens, a slit, a first collimating lens, a second collimating lens, a VPHG, a high-speed camera, an electro-optical converter, a photoelectric converter, an oscilloscope, and a computer, wherein;

[0007] The impulse voltage generator is connected to the high-voltage electrode via a bare copper wire, the height of the high-voltage electrode from the ground is 1m, the impulse voltage generator generates a 250 / 2500μs standard operating impulse voltage waveform, and generates a pilot discharge channel under the high-voltage electrode;

[0008] The condenser lens is placed 1-2m away from the high-voltage electrode, and the light beam emitted by the pilot discharge channel is focused on the left focal point through the condenser lens;

[0009] The slit is placed at the left focus of the condenser lens, the slit is placed vertically, and the center of the slit and the center of the condenser lens are placed on the same horizontal line;

[0010] The first collimating lens is placed at a distance from the slit equal to its own focal length, and the light beam passing through the slit is emitted as a parallel light beam through the first collimating lens;

[0011] The VPHG is placed between the first collimating lens and the second collimating lens, and the distance between the center vertical line of the VPHG and the first collimating lens and the second collimating lens is the same. The parallel light beam emitted by the first collimating lens is split by the VPHG, and the split light beam is emitted from the VPHG in parallel.

[0012] The second collimating lens (i.e., the high-speed camera lens) is used to converge the parallel split light beam emitted by the VPHG onto the CMOS plane of the high-speed camera for imaging;

[0013] The condenser lens, the slit, the first collimating lens, the VPHG, the second collimating lens and the high-speed camera are placed on the same horizontal line;

[0014] The high-speed camera is used to record the original spectrum;

[0015] The computer is connected to the high-speed camera by a network cable and is used to receive the time-domain continuous pilot channel emission spectrum shot by the high-speed camera.

[0016] Optionally, the trigger signal transmission circuit of the high-speed camera includes:

[0017] The impulse voltage generator and the voltage divider are connected via a wire;

[0018] The voltage divider is connected to the oscilloscope via a coaxial cable;

[0019] The oscilloscope receives the voltage signal from the voltage divider to display and store the waveform;

[0020] The oscilloscope sets the trigger mode and trigger level, and the trigger voltage is set to 500mV. When the voltage divider voltage signal received by the oscilloscope reaches the trigger level, the oscilloscope outputs a trigger signal;

[0021] The trigger signal is converted into an optical signal by a photoelectric converter, and then converted into an electrical signal by connecting the photoelectric converter through an optical fiber;

[0022] The high-speed camera receives the trigger signal converted by the photoelectric converter and synchronously triggers the high-speed camera to capture the emission spectrum of the leading channel.

[0023] A method for diagnosing the electron density of a pilot channel based on a slit spectrum is implemented by the above-mentioned system for diagnosing the electron density of a pilot channel based on a slit spectrum, and comprises the following steps:

[0024] S1, obtain the time-domain continuous emission spectrum of the leading channel;

[0025] S2, based on the emission spectrum of the leading channel, the computer program identified and located the OI777.4 nm line;

[0026] S3, extracting the spectrum data of the OI777.4nm spectrum line at the height position H at time t, and fitting the OI777.4nm atomic spectrum line based on the Lorenz line shape function;

[0027] S4, FWHM parameters calculated based on the fitted OI777.4nm spectrum line;

[0028] S5, based on the Stark broadening method of the O atomic spectrum, calculate the electron density of the leading channel at the height H position at time t;

[0029] S6, update and calculate the electron density of the leading channel at different times and different height positions, repeat S1-S5, until the leading channel enters the final jump stage and no longer calculates the electron density at this moment, and finally obtains the time and space distribution of the electron density of the leading channel in the development stage.

[0030] Optionally, S1 includes acquiring the original emission spectrum of the leading channel at the height position H at time t with a time resolution higher than 3 μs.

[0031] Optionally, S2 includes identifying and locating the OI777.4nm spectral line according to the feature with the maximum spectral line intensity based on the acquired leading channel emission spectrum.

[0032] Optionally, the S3 includes:

[0033] Based on the identified and located OI777.4nm spectrum line, the vertical channel part with spectral resolution greater than the resolution threshold in the pilot channel is selected to extract the spectral data points with equal number of spectral data points around the central wavelength of the OI777.4nm spectrum line;

[0034] The OI777.4nm spectrum is fitted using the Lorenz function and is expressed as:

[0035]

[0036] Where A is the area enclosed by the spectral line shape, ω is the FWHM parameter, and x c is the central wavelength of the spectral line, y 0 is the background value of the spectral line intensity, x is the spectral line wavelength value, and y is the spectral line intensity value.

[0037] Optionally, the S4 includes:

[0038] Based on the fitted OI777.4nm spectrum, the FWHM parameters of the spectrum were obtained and the electron density of the leading channel was calculated;

[0039] The wavelength values ​​corresponding to the central wavelength of the OI777.4nm spectral line at half the spectral line intensity are Δω 1 and Δω 2 , then the difference between the two wavelength values ​​is the FWHM parameter of the OI777.4nm spectrum line, expressed as:

[0040] FWHM=Δω 2 -Δω 1 .

[0041] Optionally, the S5 includes:

[0042] The electron density of the leading channel was calculated based on the FWHM parameters of the OI777.4nm spectral line;

[0043] The Stark broadening of the OI atomic spectral line with a wavelength of 777.4 nm is calculated as:

[0044]

[0045] Calculation of the electron density n of the leading channel based on the FWHM parameters of the OI777.4nm spectrum e , expressed as:

[0046]

[0047] Where ω(T) is the Stark broadening coefficient.

[0048] Beneficial effects of the present invention:

[0049] The present invention adopts a spectrometer design combining a high-speed camera with a VPH grating, which not only improves the spectral resolution and spectral dispersion, but also greatly improves the time resolution, and can realize the time-domain continuous diagnosis of the electron density of the leader discharge channel. The collected time-domain continuous spectral data is processed by a computer, and the OI777.4nm spectrum line diagram is fitted, and the FWHM parameters of the spectrum line are further calculated, so as to accurately obtain the electron density in the leader channel. The evolution characteristics of the physical characteristic parameters in the leader channel during the long gap discharge process can be effectively described, and high-precision calculation of the electron density can be achieved without measuring the temperature.

[0050] The present invention, through the diagnostic system, has a simple structure and is easy to build, has high device replaceability and integration, is particularly suitable for discharge observation in the laboratory, and the system does not need to rely on the pilot channel to meet the LTE condition, and can be widely used in various discharge experiments. At the same time, the system improves the time resolution and spatial resolution on the basis of providing high spectral resolution, ensures high diagnostic accuracy, and enhances the monitoring ability of the electron density change in the discharge channel. This method enables the change of electron density to be monitored comprehensively and in real time, which helps to deeply understand the physical mechanism and characteristics of the discharge process. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0052] Figure 1 It is a schematic diagram of a pilot channel electron density diagnosis system based on slit spectroscopy according to an embodiment of the present invention;

[0053] Figure 2 It is a schematic diagram of calculating the FWHM parameter in the leading channel electron density diagnosis method based on the slit spectrum according to an embodiment of the present invention;

[0054] Figure 3 Schematic diagram of the diagnostic method flow in an embodiment of the present invention. DETAILED DESCRIPTION

[0055] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. At the same time, it is explained here that in order to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art may also adopt other alternatives to implement some known technologies; and the accompanying drawings are only for more specific description of the embodiments, and are not intended to specifically limit the present invention.

[0056] It should be noted that the references to "one embodiment", "an embodiment", "an exemplary embodiment", "some embodiments" and the like in the specification indicate that the embodiments described may include specific features, structures or characteristics, but not every embodiment may include the specific features, structures or characteristics. In addition, when a specific feature, structure or characteristic is described in conjunction with an embodiment, it should be within the knowledge of a person skilled in the art to implement such feature, structure or characteristic in conjunction with other embodiments (whether or not explicitly described).

[0057] In general, a term can be understood, at least in part, from its use in context. For example, depending, at least in part, on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in the singular sense, or can be used to describe a combination of features, structures, or characteristics in the plural sense. Additionally, the term "based on" can be understood as not necessarily intended to convey an exclusive set of factors, but can instead, depending, at least in part, on the context, allow for the presence of other factors that are not necessarily explicitly described.

[0058] like Figure 1 As shown, a pilot channel electron density diagnostic system based on slit spectroscopy includes an impulse voltage generator, a high voltage electrode, a focusing lens, a slit, a first collimating lens, a second collimating lens, a VPHG, a high-speed camera, an electro-optical converter, a photoelectric converter, an oscilloscope, and a computer, wherein;

[0059] The impulse voltage generator is connected to the high-voltage electrode through a bare copper wire. The height of the high-voltage electrode from the ground is about 1m. The impulse voltage generator generates a 250 / 2500μs standard operating impulse voltage waveform to generate a pilot discharge channel under the high-voltage electrode.

[0060] The condenser lens is placed 1-2m away from the high-voltage electrode. The light beam emitted by the pilot discharge channel is focused on the left focal point through the condenser lens, so as to produce a uniform light beam and reduce the generation of stray light.

[0061] The slit is placed at the left focus of the condenser lens, the slit is placed vertically, and the center of the slit and the center of the condenser lens are placed on the same horizontal line;

[0062] The first collimating lens is placed at a distance from the slit equal to its focal length, and the light beam passing through the slit is emitted as a parallel light beam through the first collimating lens;

[0063] The VPHG is placed between the first collimating lens and the second collimating lens, and the distance between the center vertical line of the VPHG and the two collimating lenses is the same. The parallel light beam emitted by the first collimating lens is split by the VPHG, and the split light beam is emitted from the VPHG in parallel;

[0064] The second collimating lens is the high-speed camera lens, which is used to converge the parallel split beam emitted by the VPHG onto the CMOS plane of the high-speed camera for imaging;

[0065] The condenser lens, the slit, the first collimating lens, the VPHG, the second collimating lens and the high-speed camera are placed on the same horizontal line;

[0066] A high-speed camera was used to record the raw spectra;

[0067] The computer and the high-speed camera are connected by a network cable to receive the time-domain continuous pilot channel emission spectrum captured by the high-speed camera. The high-speed camera needs a trigger signal to complete the spectrum capture;

[0068] The following is the trigger signal transmission circuit of the high-speed camera:

[0069] The impulse voltage generator and the voltage divider are connected via a wire;

[0070] The voltage divider is connected to the oscilloscope via a coaxial cable;

[0071] The oscilloscope receives the voltage signal from the voltage divider to display and store the waveform;

[0072] The oscilloscope sets the trigger mode and trigger level. The trigger level is set to 500mV. When the voltage signal of the voltage divider received by the oscilloscope reaches the trigger level, the oscilloscope outputs a trigger signal.

[0073] The trigger signal is converted into an optical signal by a photoelectric converter, and then converted into an electrical signal by connecting the photoelectric converter through an optical fiber;

[0074] The high-speed camera receives the trigger signal converted by the photoelectric converter and synchronously triggers the high-speed camera to capture the emission spectrum of the leading channel.

[0075] The focusing lens adopts a double convex lens with a light aperture of 10 cm and a focal length of 0.5 m. The distance between the pilot discharge channel and the focusing lens is greater than 0.5 m.

[0076] The slit is placed on the left side of the focusing lens, 0.5m away from the central axis of the focusing lens.

[0077] The first collimating lens is a convex lens with a light aperture of 10 cm and a focal length of 10 cm, and the distance between the first collimating lens and the slit is 1.0 m.

[0078] The VPHG is placed between the first collimating lens and the second collimating lens, and the distance between the two collimating lenses is 0.3 m.

[0079] The second collimating lens uses an objective lens adapted to a high-speed camera, and uses a lens with a focal length range of 50-100 mm and an aperture of f / 1.2.

[0080] The high-speed camera was set to a shooting frequency of 300,000 frame / s, an exposure time of 3 μs, and a spectral response range of 400-1000 nm to obtain a time-domain continuous leading channel emission spectrum.

[0081] like Figure 2-Figure 3 As shown, a pilot channel electron density diagnosis method based on slit spectrum is implemented by the above-mentioned pilot channel electron density diagnosis system based on slit spectrum, comprising the following steps:

[0082] S1, obtain the original emission spectrum of the leading channel in the time domain;

[0083] S2, based on the emission spectrum of the leading channel, the computer program identified and located the OI777.4 nm line;

[0084] S3, extracting the spectrum data of the OI777.4nm spectrum line at the height position H at time t, and fitting the OI777.4nm atomic spectrum line based on the Lorenz line shape function;

[0085] S4, FWHM parameters calculated based on the fitted OI777.4nm spectrum line;

[0086] S5, based on the Stark broadening method of the O atomic spectrum, calculate the electron density of the leading channel at the height H position at time t;

[0087] S6, update and calculate the electron density of the leading channel at different times and different height positions, repeat steps S1-S5 until the leading channel enters the final jump stage and no longer calculates the electron density at this moment, and finally obtains the time and space distribution of the electron density of the leading channel in the development stage.

[0088] Obtain the time-domain continuous raw emission spectrum of the leading channel, including:

[0089] Under certain atmospheric pressure standards and ambient humidity conditions, the time-domain continuous original emission spectrum of the leading channel is obtained through the above-mentioned leading channel electron density diagnostic system; wherein, the diagnostic system obtains the original emission spectrum of the leading channel at the height position H at time t with a time resolution better than 3μs.

[0090] Based on the emission spectrum of the leading channel, the computer program identified and located the OI777.4nm spectral line, including:

[0091] Based on the original emission spectrum of the leading channel obtained, the OI777.4nm spectral line was identified and located according to the feature with the largest spectral line intensity.

[0092] Extract the spectrum data of the OI777.4nm line at the height position H at time t, and fit the OI777.4nm atomic line based on the Lorenz line shape function, including:

[0093] Based on the identified and located OI777.4nm spectrum line, the vertical channel part with spectral resolution greater than the resolution threshold in the pilot channel is selected, and the spectral data points with equal number of left and right of the central wavelength of the OI777.4nm spectrum line are extracted, and the OI777.4nm spectrum line graph is fitted using the Lorenz function:

[0094]

[0095] Where A is the area enclosed by the spectral line shape; ω is the FWHM parameter; x c is the central wavelength of the spectral line; y 0 is the background value of the spectral line intensity; x is the spectral line wavelength value; y is the spectral line intensity value.

[0096] The FWHM parameters are calculated based on the fitted OI777.4nm spectrum, including:

[0097] Based on the fitted OI777.4nm spectrum, the FWHM parameters of the spectrum can be obtained to calculate the electron density of the leading channel; the wavelength values ​​corresponding to the center wavelength value of the OI777.4nm spectrum at half the intensity of the spectrum are Δω 1 and Δω 2 , then the difference between the two wavelength values ​​is the FWHM parameter of the OI777.4nm spectrum line, that is:

[0098] FWHM=Δω 2 -Δω 1 ;

[0099] Based on the Stark broadening method of the O atomic spectrum, the electron density of the leading channel at the height H at time t is calculated, including:

[0100] The electron density of the leading channel was calculated based on the FWHM parameters of the OI777.4nm spectral line;

[0101] Calculate the Stark broadening of the OI atomic line at a wavelength of 777.4 nm:

[0102]

[0103] Calculation of the electron density n of the leading channel based on the FWHM parameters of the OI777.4nm spectrum e :

[0104]

[0105] Where ω(T) is the Stark broadening coefficient, which is a function of temperature T. Since the temperature of the pilot channel is basically maintained in the range of 3000-6000K, ω(T) can be regarded as a constant, which is 0.00228nm.

[0106] The present invention covers any substitution, modification, equivalent method and scheme made on the essence and scope of the present invention. In order to make the public have a thorough understanding of the present invention, specific details are described in detail in the following preferred embodiments of the present invention, but those skilled in the art can fully understand the present invention without the description of these details. In addition, in order to avoid unnecessary confusion about the essence of the present invention, well-known methods, processes, procedures, components and circuits are not described in detail.

[0107] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A pilot channel electron density diagnostic system based on slit spectroscopy, characterized in that: It includes an impulse voltage generator, a high voltage electrode, a focusing lens, a slit, a first collimating lens, a second collimating lens, a VPHG, a high-speed camera, an electro-optical converter, a photoelectric converter, an oscilloscope, and a computer, wherein; The impulse voltage generator is connected to the high-voltage electrode via a bare copper wire, the height of the high-voltage electrode from the ground is 1m, the impulse voltage generator generates a 250 / 2500μs standard operating impulse voltage waveform, and generates a pilot discharge channel under the high-voltage electrode; The condenser lens is placed 1-2m away from the high-voltage electrode, and the light beam emitted by the pilot discharge channel is focused on the left focal point through the condenser lens; The slit is placed at the left focus of the condenser lens, the slit is placed vertically, and the center of the slit and the center of the condenser lens are placed on the same horizontal line; The first collimating lens is placed at a distance from the slit equal to its own focal length, and the light beam passing through the slit is emitted as a parallel light beam through the first collimating lens; The VPHG is placed between the first collimating lens and the second collimating lens, and the distance between the center vertical line of the VPHG and the first collimating lens and the second collimating lens is the same. The parallel light beam emitted by the first collimating lens is split by the VPHG, and the split light beam is emitted from the VPHG in parallel. The second collimating lens is used to converge the parallel split light beam emitted by the VPHG onto the CMOS plane imaging of the high-speed camera; The condenser lens, the slit, the first collimating lens, the VPHG, the second collimating lens and the high-speed camera are placed on the same horizontal line; The high-speed camera is used to record the original spectrum; The computer is connected to the high-speed camera by a network cable and is used to receive the time-domain continuous pilot channel emission spectrum shot by the high-speed camera.

2. A pilot channel electron density diagnostic system based on slit spectrum according to claim 1, characterized in that: The trigger signal transmission circuit of the high-speed camera includes: The impulse voltage generator and the voltage divider are connected via a wire; The voltage divider is connected to the oscilloscope via a coaxial cable; The oscilloscope receives the voltage signal from the voltage divider to display and store the waveform; The oscilloscope sets the trigger mode and trigger level. The trigger level is set to 500mV. When the voltage signal of the voltage divider received by the oscilloscope reaches the trigger level, the oscilloscope outputs a trigger signal. The trigger signal is converted into an optical signal by a photoelectric converter, and then converted into an electrical signal by connecting the photoelectric converter through an optical fiber; The high-speed camera receives the trigger signal converted from the photoelectric converter and synchronously triggers the high-speed camera to capture the emission spectrum of the leading channel.

3. A method for diagnosing electron density in a pilot channel based on slit spectroscopy, implemented by a system for diagnosing electron density in a pilot channel based on slit spectroscopy according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1, obtain the time-domain continuous emission spectrum of the leading channel; S2, based on the emission spectrum of the leading channel, the computer program identified and located the OI777.4 nm line; S3, extracting the spectrum data of the OI777.4nm spectrum line at the height position H at time t, and fitting the OI777.4nm atomic spectrum line based on the Lorenz line shape function; S4, FWHM parameters calculated based on the fitted OI777.4nm spectrum line; S5, based on the Stark broadening method of the O atomic spectrum, calculate the electron density of the leading channel at the height H position at time t; S6, update and calculate the electron density of the leading channel at different times and different height positions, repeat S1-S5, until the leading channel enters the final jump stage and no longer calculates the electron density at this moment, and finally obtains the time and space distribution of the electron density of the leading channel in the development stage.

4. A method for diagnosing electron density in a pilot channel based on slit spectroscopy according to claim 3, characterized in that: The S1 includes acquiring the original emission spectrum of the leading channel at the height position H at time t with a time resolution higher than 3 μs.

5. A method for diagnosing electron density in a pilot channel based on slit spectroscopy according to claim 4, characterized in that: The S2 includes identifying and locating the OI777.4nm spectral line according to the feature with the largest spectral line intensity based on the acquired leading channel emission spectrum.

6. A method for diagnosing electron density in a pilot channel based on slit spectroscopy according to claim 5, characterized in that: The S3 includes: Based on the identified and located OI777.4nm spectrum line, the vertical channel part with spectral resolution greater than the resolution threshold in the pilot channel is selected to extract the spectral data points with equal number of spectral data points around the central wavelength of the OI777.4nm spectrum line; The OI777.4nm spectrum is fitted using the Lorenz function and is expressed as: Where A is the area enclosed by the spectral line shape, ω is the FWHM parameter, and x c is the central wavelength of the spectral line, y0 is the background value of the spectral line intensity, x is the spectral line wavelength value, and y is the spectral line intensity value.

7. A method for diagnosing electron density in a pilot channel based on slit spectroscopy according to claim 6, characterized in that: The S4 includes: Based on the fitted OI777.4nm spectrum, the FWHM parameters of the spectrum were obtained and the electron density of the leading channel was calculated; The wavelength values ​​corresponding to the half of the intensity of the central wavelength value of the OI777.4nm spectrum line are Δω1 and Δω2 respectively. The difference between the two wavelength values ​​is the FWHM parameter of the OI777.4nm spectrum line, which is expressed as: FWHM=Δω2-Δω1.

8. The method for diagnosing electron density in a pilot channel based on slit spectroscopy according to claim 7, characterized in that: The S5 includes: The electron density of the leading channel was calculated based on the FWHM parameters of the OI777.4nm spectral line; The Stark broadening of the OI atomic spectral line with a wavelength of 777.4 nm is calculated as: Calculation of the electron density n of the leading channel based on the FWHM parameters of the OI777.4nm spectrum e , expressed as: Where ω(T) is the Stark broadening coefficient.

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