Synchronous alignment device and method for short-pulse laser Thomson scattering signal light spots

Abstract

The invention discloses a synchronous alignment device and method for short-pulse laser Thomson scattering signal light spots to achieve high-precision synchronous monitoring of light spots positions. Two positions are selected from a signal receiving optical fiber bundle array; an optical fiber receiving end surface is equally divided into left and right two beams and the length difference between the two beams is 10m; short-pulse signals are transmitted into an original spectrometer and an APD detector in a manner of staggering about 50ns; and after data are obtained through a high-frequency collection system, two pulse signals are analyzed and calculated, the signal intensity ratio of the two pulse signals is used for analyzing real-time offset of the optical fiber end surface and then a three-dimensional optical fiber bracket is adjusted through a control system, so that the offset is eliminated and the system precision is improved. The spectrum shape and strength after the two pulse signals are superposed are used for calculating the electron temperature and density respectively. By the method disclosed by the invention, the relative positions of the signal receiving optical fiber end surface and the scattering light spots are directly and accurately detected through the device disclosed by the invention; and the method and the device are suitable for collection of short-pulse laser Thomson scattering signals and the like.

Description

Technical field [0001] The invention relates to the technical field of laser scattering diagnosis, in particular to a device and method for synchronously aligning short-pulse laser Thomson scattering signal spots. Background technique [0002] High-temporal resolution and high-precision laser Thomson scattering diagnosis is an important direction of current magnetic confinement nuclear fusion plasma diagnosis. Thomson Scattering Diagnosis has the characteristics of high measurement accuracy, short single pulse time (~10ns), no need for inversion of diagnostic data (accurate spatial positioning), and it can measure electron temperature and density data at the same time and in the same area. It is a recognized electron temperature and The most accurate means of density distribution measurement. [0003] At present, Thomson scattering diagnosis is widely used in magnetic confinement nuclear fusion devices such as tokamak and stellar simulators all over the world. Typical examples are...

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Problems solved by technology

However, this method is neither stable nor accurate enough, nor can it obtain synchronous monitoring data at the moment of pulsed laser scattering.

Another method is to use multiple optical fibers to arrange on the fiber optic bracket and introduce the scattered signal into the spectrometer and signal detector, and analyze the data obtained by the detector to determine whether the scattered signal spot has completely entered the receiving end face of the fiber bundle, but this method At the cost of losing the spatial resolution of the system, reducing system performance, and additionally requiring multiple spectrometers and detectors, the cost is expensive

In addition, the sensitivity of each detector and the passband wavelength of each interference filter are different, which is not suitable for accurate comparison of weak signals

In summary, the above methods all have shortcomings or deficiencies, and are not suitable for the simultaneous monitoring of the scattering spot position of the Thomson scattering diagnostic system with high precision and high spatiotemporal resolution

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