Preliminary Visual Analysis For Numerical Simulation Results Of Coronal Interplanetary Solar Storm Propagation

Solar storms affect the sun-terrestrial space environment,and simulating the propagation process of solar storms in the intercoronal interplanetary space based on numerical models is an important means of forecasting and serving the space environment.Using various visual analysis methods to explore the evolution of characteristic bodies in the numerical simulation results of solar storms is an important method to verify the validity of numerical models.Coronal mass ejection(CME)is a typical activity of solar storm.In this thesis,a variety of visual analysis methods are designed to explore and analyze the evolution process of CME,so as to quickly realize the analysis,understanding and verification of numerical simulation results,and finally realize effective monitoring,diagnosis and prediction of disastrous space weather.The density of the interplanetary medium in large-scale interplanetary space decays sharply with the distance from the heliocentric,showing the characteristics of varying across multiple orders of magnitude.CME in interplanetary space disturbs the density most intuitively,and the number density is an important parameter for analyzing CME propagation.In order to analyze the global CME propagation process,this thesis proposes an algorithm to eliminate the radial magnitude gradient of volume data in three-dimensional space based on the normalized radial gradient filtering algorithm of two-dimensional optical imaging.Remove the radially large magnitude falloff feature,and test the effect of the method from both statistical and visual effects.The experimental results show that this method eliminates the radial magnitude attenuation characteristic of density in the numerical simulation results of solar storms,and the radial numerical difference is less than 10.The co-transformation interaction region(CIR)and CME structure are more pronounced.In order to quickly understand the massive data generated by numerical simulation and characterize the complex interaction process of CME propagation in interplanetary space,this thesis analyzes the numerical simulation results of the evolution process of CME interplanetary space from three perspectives: target detection and motion parameter estimation,volume rendering algorithm and 3D reconstruction of point cloud.Firstly,the CME detection algorithm is designed by combining the KNN background separation method and the saliency algorithm of Frequency Tuned(FT)full frequency domain analysis,integrating the temporal and spatial characteristics of CME to realize the detection of the CME area of the cut plane,and based on the detection results,the CME velocity size,direction and expansion width are calculated in real time.providing reference for the position and movement process of the CME.Secondly,the color mapping function and opacity mapping rules in volume rendering are designed according to the data gradient,image edge,and CME detection results,so as to realize the 3D visualization effect including the internal structure of CME.Finally,based on the 3D reconstruction algorithm and statistical filtering idea,the 3D structure of the CME at each moment is reconstructed,which avoids the error caused by the traditional single threshold screening of the CME area,and provides a reference for the evolution analysis of the morphological characteristics of the CME in the numerical simulation results.The experimental results show that the visualization and automatic analysis scheme can well represent the evolution process of CME in the process of coronal interplanetary propagation,the interaction between CME and CIR,and basically restore the morphological structure of CME,which is helpful for the rapid understanding of the CME propagation process and its complex structure in the numerical simulation results.