강하게 결합된 복잡 플라즈마 내에서의 원자 현상

Abstract

본 논문에서 다양한 플라즈마 내에서의 원자 충돌 및 복사 현상에 대한 연구를 수행하였다. 약하게 결합된 플라즈마의 경우에는 차폐된 입자들의 상호작용 potential을 일반적인 Debye-Hückel model을 사용하여 설명할 수 있으나, 고밀도의 양자 플라즈마와 비열적 Lorentzian 플라즈마, 그리고 분진 플라즈마에서는 플라즈마 가림효과 뿐만 아니라 양자효과와 비열적효과, 그리고 이온 wake 효과 등을 고려해주어야 함으로 본 논문은 Lorentzian 플라즈마, 양자 플라즈마, 그리고 분진 플라즈마 내에서의 원자 충돌과 복사 현상에 작용하는 여러 형태의 플라즈마 가림효과를 연구하였다. 논문의 첫 부분에서는 Lorentzian 플라즈마 내에서의 원자현상에 대하여 연구하였다. 첫째로, 비열적 천체 플라즈마에서 전자충돌에 의한 수소분자의 분리와 여기현상을 연구하였다. 전자 여기 산란단면적에 대한 fitting formula를 사용하여 전자여기 rate coefficient를 spectral index와 온도의 함수로 표현하고, 천체플라즈마의 다양한 온도 영역에서 전자 여기 rate coefficient의 변화를 조사하였다. 낮은 플라즈마 온도에서 non-Maxwellian 플라즈마에서의 수소 분자의 여기 rate coefficient가 Maxwellian 플라즈마 내에서 보다 작아지지만, 높은 플라즈마 온도에서는 non-Maxwellian 플라즈마에서 더욱 커짐을 규명하였다. 두번째로, 부분적으로 이온화된 generalized Lorentzian 플라즈마 내에서 polarization 전자포획에 의한 negative 수소이온의 형성에 작용하는 비열적 가림효과를 Bohr-Lindhard 방법을 이용하여 연구하였다. 작은 Debye 반경에서 플라즈마의 비열적 성질이 negative 수소이온 형성반경을 증가시킴을 규명하였고, 비열적 효과가 negative 수소이온 형성 cross section을 증가시킴을 밝혀내었다. 그리고 작은 spectral index에 대하여 negative 수소이온 형성 cross section이 Debye 반경의 증가에 따라 현저히 감소하게 됨을 알아내었다. 세번째로, Lorentzian 플라즈마에서 Thomson 산란에 미치는 비열적 효과와 가림효과에 대하여 연구하였다. 비열적 효과는 Lorentzian 플라즈마에서 Thomson 산란 과정을 억제시킴을 밝혀내었다. 그리고 비열적 효과는 중간의 wave number에서 더 중요함을 규명하였다. 논문의 두번째 부분에서는 양자 플라즈마 내에서의 원자현상에 대하여 연구하였다. 첫째로, 밀도가 높은 semiclassical 플라즈마에서 전이 제동복사현상에 미치는 양자효과에 대하여 연구하였다. Semiclassical 플라즈마에서 양자효과는 전환 제동복사 스펙트럼을 크게 증가시킴을 밝혀내었다. 그리고 soft-photon 영역에서 제동복사 스펙트럼의 영역은 Debye radius보다 큼을 밝히고, hard-photon 영역에서 Debye sphere 보다 작아짐을 규명하였다. 두번째로, 강하게 결합된 고밀도 플라즈마 내에서 polarization 운동량 전이 충돌에 작용하는 양자 동적 가림효과를 Faxen-Holtzmark 이론을 이용하여 연구하였다. 동적 가림효과는 산란위상변화와 polarization 운동량 전이 산란단면적을 증가시킴을 규명하였다. 그리고 열에너지와 de Broglie 파장의 변화로 인한 운동량 전이 충돌에 작용하는 다양한 양자효과를 조사하였다. 논문의 마지막부분에서는 분진 플라즈마 내에서의 원자현상에 대하여 연구하였다. 첫째로,분진 플라즈마 내에서 전자-분진 충돌에 작용하는 비선형 동적 가림효과 영향을 연구하였다. 비선형 동적 플라즈마 가림효과가 eikonal 위상변위의 크기를 현저히 증가시킴을 밝혀내었고, 위상변위의 크기가 열에너지의 증가에 따라 감소함을 규명하였다. 그리고 미분산란단면적이 진동하며 진동의 최고점이 열에너지가 증가함에 따라 충돌의 중심으로 접근하고, 총 eikonal 산란단면적은 열에너지가 증가함에 따라 감소함을 밝혀내었다. 마지막으로, 복합 분진 플라즈마에서 Coulomb ion drag에 작용하는 이온 wake 효과에 대하여 연구하였다. 이온 wake 효과는 Coulomb ion drag force를 크게 증가시킴을 규명하였고, Coulomb ion drag force에 미치는 이온 wake 효과는 Debye length가 증가함에 따라 증가함을 밝혀내었다. 그리고 운동량 전이 산란단면적에 미치는 이온 wake 효과와 Coulomb ion drag force는 열적 Mach number가 증가됨에 따라, 즉 플라즈마 온도가 감소됨에 따라 증가하고, 특히 Coulomb ion drag force는 dust 사이즈가 작아질수록 커짐을 규명하였다.|In this thesis, the atomic processes are investigated in strongly coupled complex plasmas. In the first part of this thesis, the atomic processes in Lorentzian plasmas are investigated. First, the electronic transitions of the molecular hydrogen by the electron impacts are investigated in astrophysical Lorentzian plasmas. The useful fitting formulas for the excitation cross sections are employed in order to obtain the electronic excitation rate coefficients of the molecular hydrogen as functions of the spectral index and temperature in Lorentzian plasmas. In low temperature regions, it is found that the excitation rate coefficients of the molecular hydrogen in non-Maxwellian plasmas are smaller than those in Maxwellian plasmas. However, in high temperature regions the excitation rate coefficients of the molecular hydrogen in non-Maxwellian plasmas are found to be greater than those in Maxwellian plasmas. Second, the influence of the nonthermal shielding on the formation of the negative hydrogen ion by the polarization electron capture are investigated in partially ionized generalized Lorentzian plasmas. The Bohr-Lindhard method has been applied to obtain the negative hydrogen formation radius and cross section. The result shows that the nonthermal character of the Lorentzian plasma enhances the formation radius of the negative hydrogen, especially, for small Debye radius domains. It is found that the nonthermal effect increases the formation cross section of the negative hydrogen. In addition, the nonthermal and plasma screening effects on the Thomson scattering process are investigated in generalized Lorentzian electron plasmas. The Thomson scattering cross section is obtained as a function of the spectral index, wave number, and Debye length. It is found that the nonthermal effect suppresses the Thomson scattering process in Lorentzian plasmas. In the second part of this thesis, the atomic processes are investigated in quantum plasmas. First, the quantum effects on the transition bremsstrahlung spectrum due to the polarization interaction between the electron and Debye shielding cloud are investigated in dense semiclassical plasmas. The impact-parameter analysis with the screened effective pseudopotential taking into account the quantum and plasma screening effects is employed to obtain the bremsstrahlung radiation cross section. The result shows that the quantum effect strongly suppresses the transition bremsstrahlung radiation spectrum in semiclassical plasmas. It is also found that the domain of the bremsstrahlung spectrum in the soft-photon radiation case is greater than the Debye radius. However, the bremsstrahlung domain in the hard-photon radiation case is found to be localized within the Debye sphere. In addition, the influence of the quantum dynamic shielding on the polarization momentum transport collision is investigated by using the Faxen-Holtzmark theory in strongly coupled dense plasmas. The electron-atom polarization momentum transport cross section is derived including the quantum dynamic shielding effects. It is found that the dynamic shielding enhances the scattering phase shift as well as the polarization momentum transport cross section. The variation of quantum effect on the momentum transport collision due to the change of thermal energy and de Broglie wavelength is also discussed. In the last part of this thesis, the atomic processes in dusty plasmas are investigated. First, the nonlinear dynamic plasma screening effects on the elastic electron-dust grain collision are investigated in dusty plasmas. The results show that the nonlinear dynamic screening effect significantly increases the magnitude of the eikonal scattering phase shift. It is also found that the magnitude of the phase shift decreases with an increase of the thermal energy. It is also found that the total eikonal cross section decreases with an increase of the thermal energy. In addition, the ion wake effects on the Coulomb drag force are investigated in complex dusty plasmas. It is shown that the ion wake effects significantly enhance the Coulomb ion drag force. It is also found that the ion wake effects on the Coulomb drag force increase with an increase of the Debye length. It is also found that the Coulomb ion drag force would be stronger for smaller dust grains.; In this thesis, the atomic processes are investigated in strongly coupled complex plasmas. In the first part of this thesis, the atomic processes in Lorentzian plasmas are investigated. First, the electronic transitions of the molecular hydrogen by the electron impacts are investigated in astrophysical Lorentzian plasmas. The useful fitting formulas for the excitation cross sections are employed in order to obtain the electronic excitation rate coefficients of the molecular hydrogen as functions of the spectral index and temperature in Lorentzian plasmas. In low temperature regions, it is found that the excitation rate coefficients of the molecular hydrogen in non-Maxwellian plasmas are smaller than those in Maxwellian plasmas. However, in high temperature regions the excitation rate coefficients of the molecular hydrogen in non-Maxwellian plasmas are found to be greater than those in Maxwellian plasmas. Second, the influence of the nonthermal shielding on the formation of the negative hydrogen ion by the polarization electron capture are investigated in partially ionized generalized Lorentzian plasmas. The Bohr-Lindhard method has been applied to obtain the negative hydrogen formation radius and cross section. The result shows that the nonthermal character of the Lorentzian plasma enhances the formation radius of the negative hydrogen, especially, for small Debye radius domains. It is found that the nonthermal effect increases the formation cross section of the negative hydrogen. In addition, the nonthermal and plasma screening effects on the Thomson scattering process are investigated in generalized Lorentzian electron plasmas. The Thomson scattering cross section is obtained as a function of the spectral index, wave number, and Debye length. It is found that the nonthermal effect suppresses the Thomson scattering process in Lorentzian plasmas. In the second part of this thesis, the atomic processes are investigated in quantum plasmas. First, the quantum effects on the transition bremsstrahlung spectrum due to the polarization interaction between the electron and Debye shielding cloud are investigated in dense semiclassical plasmas. The impact-parameter analysis with the screened effective pseudopotential taking into account the quantum and plasma screening effects is employed to obtain the bremsstrahlung radiation cross section. The result shows that the quantum effect strongly suppresses the transition bremsstrahlung radiation spectrum in semiclassical plasmas. It is also found that the domain of the bremsstrahlung spectrum in the soft-photon radiation case is greater than the Debye radius. However, the bremsstrahlung domain in the hard-photon radiation case is found to be localized within the Debye sphere. In addition, the influence of the quantum dynamic shielding on the polarization momentum transport collision is investigated by using the Faxen-Holtzmark theory in strongly coupled dense plasmas. The electron-atom polarization momentum transport cross section is derived including the quantum dynamic shielding effects. It is found that the dynamic shielding enhances the scattering phase shift as well as the polarization momentum transport cross section. The variation of quantum effect on the momentum transport collision due to the change of thermal energy and de Broglie wavelength is also discussed. In the last part of this thesis, the atomic processes in dusty plasmas are investigated. First, the nonlinear dynamic plasma screening effects on the elastic electron-dust grain collision are investigated in dusty plasmas. The results show that the nonlinear dynamic screening effect significantly increases the magnitude of the eikonal scattering phase shift. It is also found that the magnitude of the phase shift decreases with an increase of the thermal energy. It is also found that the total eikonal cross section decreases with an increase of the thermal energy. In addition, the ion wake effects on the Coulomb drag force are investigated in complex dusty plasmas. It is shown that the ion wake effects significantly enhance the Coulomb ion drag force. It is also found that the ion wake effects on the Coulomb drag force increase with an increase of the Debye length. It is also found that the Coulomb ion drag force would be stronger for smaller dust grains.