Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： Sprites are the transient luminous events above very active thunderstorms and are the direct evidence of the energy in troposphere coupled to the upper atmosphere. The emissive spectrum study is the important means to understand the energy injected into upper atmosphere and regional ionization, the electron energy distribution during the whole event. These parameters are useful for the study of sprites' physical mechanism, in addition as a kind of natural atmospheric luminous phenomenon, the emissive spectrum study is useful for providing important information to the research of atmospheric radiation background information. Based on the Boltzmann Equation to calculate the time evolution of the electron energy distribution function in a mixture of partially ionized gases with an applied electric field, the paper calculated the spectral intensity in typical emissive band for sprites. Simulation results show that the emissive intensity is more intensive with more intensive E/N and the emissive spectrum is from far ultraviolet to near infrared.
Peer Review Status:
Awaiting Review
Subjects: Geosciences >> Space Physics submitted time 2016-05-13
Abstract： The middle lightning phenomena is a key topic in the middle and upper atmosphere.In this dissertation,its emissive spectral is studied by numerical simulation.On the base of the quasi-electrostatic(QE)field excitating mechanism,the quasielectrostatic field distribution with height caused by a sudden discharge of thunderstorm cloud is calculated by single point charge model.The reduced E-field(E/N,where E is the quasielectrostatic field intensity and N is the neutral density)is inputted into the Boltzmann equation function for the electron energy distribution with time in a mixture of partially ionized gases.The excitation rate corresponding to the collisional process as a function of reduced E-field is calculated.On the base of the calculations the volume emissive rate for each emissive band is calculated,then the volume emissive rate is inputted into the atmophere radiative transfer function to obtain the radiative intensity with wavelength.Example for the excitation calculated when E/N=200Td,the radiative intensity produced thousands of rayleighs.The spectral distribution is relative to the atmospheric composition and dectection path.
Peer Review Status:Awaiting Review
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