Релятивістський розрахунок сил електрон-іонних зіткнень для багатозарядних іонів у плазмі

Ключовi слова: спектр багатозарядного іону, електрон-іонні зіткнення, квантово-електродинамічна теорія збурень.

Корчевский Д.А. Релятивистский расчет сил электрон-ионных столкновений для многозарядных ионов в плазме.- Рукопись.

Диссертация на соискание ученой степени кандидата физико-математических наук по специальности 01.04.05 - оптика и лазерная физика .-Одесский национальный университет им. И. Мечникова Министерства обра-зования и науки Украины, Одесса, 2008.

Диссертация посвящена разработке нового метода релятивистского расчета характеристик процессов электрон-ионных столкновений в плазме многозарядных ионов, который базируется на ab initio квантово-электродинамической теории возмущений для 1- и 2-квазичастичных атомных систем с генерацией калибровочно-инвариантного базиса релятивистских электронных функций «0» порядка и прецизионным учетом корреляционных эффектов как эффектов второго и выше порядков теории возмущений. Предложен новый, непертурбативный метод расчета характеристик процессов электрон-ионных столкновений во внешнем электрическом поле произвольной силы. Проведен расчет сечений и сил электронных столкновений, скоростных коэффициентов с корректным учетом релятивистских, обменно-корреляционных эффектов для возбуждения переходов из основного состояния F-,Ne- и Ar-подобных ионов с зарядом ядра Z=19-26, 56 (лучших “кандидатов” на лазерную генерацию) в 37 возбужденных состояний. Большая часть спектральных данных получена в работе с высокой точностью впервые и может быть использована в широком круге приложений в оптике и спектроскопии плазмы, лазерной физике, астрофизике и др.

Ключевые слова: спектр многозарядного иона, электрон-ионные столкновения, квантово-электродинамическая теория возмущений.

Korchevsky D.A. Relativistic calculation of strengths of electron-ion collisions for multi-charged ions in a plasma.- Manuscript.

Thesis for a candidate's degree by speciality 01.04.05 - optics and laser physics.- I.I.Mechnikov's Оdessa National University of Ministry of education and science of Ukraine, Odessa,2008.

Dissertation is devoted to carrying out a new, ab initio approach to calculating the characteristics for electron-ion collisions for complex multicharged ions in plasma. The method is based on new ab initio version of the QED perturbation theory for one- and two-quasiparticle atomic systems with using comprehensive, gauge invariant relativistic orbital basis's and precise account for the complex exchange-correlation effects as effects of the perturbation theory second and higher orders. To make approbation of new method and get new spectral data it has been carried out a relativistic calculation of the cross-sections and electron collisions strengths for a number of F-, Ne- Ar-like ions with a nuclear charge Z=17-26,56, which are the best candidates for a laser generation and construction of lasers of the short-waved range with the multicharged ions plasma as an active medium. It has been carried out calculation of the cross-sections and electron collisions strengths for excitation of transition between the fine structure levels (2p ²P_3/2 - ²P_1/2 ) of ground state for F-like ions with Z=19-26 (the incident electron energy _in=0,1294Z² еV) with accurate accounting for relativistic and exchange-correlation effects. A comparison of tested data on collision strengths with calculation results within more advanced versions of the R-matrix method (LS+JAJOM, ICFT) and experiment for F-like ions of ArX, FeXVIII has demonstrated quite high accuracy of new method. Our theory gives better agreement with experiment than the R-matrix theory. Further it has been carried out a calculation of the cross-sections and electron collisions strengths (incident electron energies 0.425, 0.5, 0.750, 1.045 кеV) for Ne-like ions ArIX, FeXVII (the best candidates for laser generation) from the ground state to 37 excited states (2s_1/22p_1/2,3/2, 2p_3/2,1/23s_1/2, 2p_3/2,1/23p_3/2,1/2 , 2p_3/2,1/23d_5/2,3/2, 2s_1/23s_1/2 , 2s_1/23p_1/2,3/2, 2s_1/23d_3/2,5/2 [J=0,1,2, 3,4]), and Nе-like ion of Ba too (the incident electron energies 5.69, 8.2 кeV). It has been shown that using the gauge-invariant basis's of relativistic orbitals and correct account for the exchange-correlation effects (the screening and polarization effects) plays a key role in reaching quite high accuracy. The corresponding contribution is about ~ 30-40%. More over, fro some states the cited corrections change the results to 2-3,5 times. Our theory provides more good agreement with experiment than alternative theories such as R-matrix approach, relativistic perturbation theory with compiled model and Dirac-Fock zeroth approximations. Firstly we have carried out a detailed studying the collision cross-sections and collision strengths (the incident electron energies 0.425,0.5,0.75,1.045 кeV) for Ne-like ions ClVIII, ArIX , CaXI, TiXIII, CrXV from the ion ground state to 37 excited states (2s_1/22p_1/2,3/2, 2p_3/2,1/23s_1/2, 2p_3/2,1/23p_3/2,1/2 , 2p_3/2,1/23d_5/2,3/2, 2s_1/23s_1/2 , 2s_1/23p_1/2,3/2, 2s_1/23d_3/2,5/2 [J=0,1,2,3,4]) and Ar-like ion of Ba (the incident electron energy 5.8, 9.5 кeV), for which there are absent exact data. It is shown that the best candidates for laser generation above studied transitions are as follows: 2p_1/23s_1/2 [J=1], 2p_3/23p_3/2 [J=0], 2p_3/23d_5/2[J=2], 2p_3/23d_5/2 [J=4], 2s_1/23s_1/2 [J=0], 2p_1/23d_3/2 [J=1]. We firstly develop an effective scheme for calculating the velocity coefficients for collision excitation of multicharged ions, which uses an energy approach to calculating collision strengths and describing the continuum electrons distribution by a relativistic Maxwell-Boltzmann distribution formula. A temperature dependence of the velocity coefficients for collision excitation of the iron Ne-like ion has been defined. It has been shown that our values for the velocity coefficients (as the collision cross-sections too) are less than the corresponding R-matrix values and are more than the similar values within the relativistic perturbation theory with zeroth compiled model approximation. Firstly a new, non-perturbation approach to calculating the electron-ion collision strengths in an external electric field of the arbitrary strength is proposed and based on the collision energy approach and operator perturbation theory. The electron collision strengths for excitation of transitions between the (2p ²P_3/2 - ²P_1/2 ) levels of ground state for F-like ions with nuclear charge Z=19-26 (field strengths ~ 10^-6, 10^-5 atomic units) are calculated. It has been shown that an external electric filed may drastically change the strengths values.

Key words: spectrum of multicharged ion, electron-ion collisions, quantum electrodynamics perturbation theory.

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