Extraction And Test Of Weak Light Signal Of Large-Angel White-Light Corograph

Coronal mass ejections(CMEs)eject large amounts of magnetized plasma from the sun’s atmosphere into interplanetary space,resulting in massive solar explosions.Especially when CME spreads to the vicinity of the earth,it will produce geomagnetic disturbances such as geomagnetic storms,ionospheric storms,auroras,etc.,which have a destructive impact on satellite operations and ground infrastructure,and are one of the main driving sources of disastrous weather in space.Therefore,continuous observation of the corona and CME in a larger field of view is extremely important for in-depth understanding of solar activity and timely space weather warning.The corona,CMEs,and solar wind disturbance structures within the heliosphere within the large-field white-light extended coronagraph are used as the observation targets.Combined with the technical advantages of the sun-centered coronagraph and the side-shielded heliospheric imager,the outer coronagraph that shields the sun in the center is used as the observation target.The field of view is extended to a half field of view of 20°(the observation field of view of the satellite at a 1AU orbit can cover 75 times the solar radius),and for the first time,it is possible to observe the weak light radiation of the inner heliosphere from the sun to the earth for the first time.At the same time,with the expansion of the observation field,it is necessary to enhance the processing and information extraction of weak light signals in a larger range,in order to better exert the observation ability of the large field of view coronagraph.This paper studies the weak light signal extraction of white light extended coronagraph with large field of view.First,the related methods of weak target image processing in the field of space detection are integrated,combined with the data processing steps of the coronagraph/heliospheric imager,and the extraction method of weak light signals matching the large field of view of the coronagraph is given.The dynamic CME signal is obtained by using the actual observation data of the HI heliospheric imager of the STEREO satellite for verification.Secondly,independently designed and built an experimental system to simulate the light radiation environment on the CME propagation path in space,and conducted ground tests on the large-field coronagraph,including:the gradient scattering light source to simulate the static F coronal background,and the optical fiber guide to simulate the discrete star points,the gaseous jet simulates the CME eruption and propagation shape,etc.After completing the test experiment and applying the coronagraph weak signal extraction process for processing,the weak simulated dynamic CME signal can be obtained from the background light with a brightness of about 2 orders of magnitude higher.Finally,in order to realize the joint observation of the large field of view coronagraph and the ground-based coronagraph,according to the morphological characteristics of the initial burst and propagation evolution of CME,based on the weak signal extraction of the coronal observation,the threshold segmentation and morphological processing methods of the differential image are used to give The data processing flow of automatic identification and real-time detection of CME signals is presented,which is ready for the application of the observation results of the large-field coronagraph to space weather forecasting.In this paper,through the related research on the extraction,processing and test verification of weak coronal signals,the key technology research of the white light extended coronagraph with large field of view has been completed.The method provides valuable technical reserves,which can be further extended and applied to the calibration and calibration of the coronagraph after the on-board operation,so as to produce more accurate scientific data.