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根据Holstein的共振辐射俘获理论,讨论了气体温度和辐射俘获下能级粒子数密度对辐射俘获上能级有效辐射寿命的影响,显示辐射俘获下能级粒子数密度是辐射俘获效应中的主导因素.计算了钙,锶,钡和汞四种离子七条共振-亚稳能级跃迁激光在不同电离率下产生共振辐射俘获效应的阈值条件,发现当电离率为5%时这类激光的出光温度与共振辐射俘获的阈值温度相一致,这与实验得出的电离率为3%—5%相符合.表明达到共振辐射俘获阈值条件是该类激光实现粒子数反转的重要因素. 相似文献
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利用的程序是基于FASTFP开发的RFP准线性Fokker-Planck程序,该程序适用于各种辅助加热和电流驱动的动力学计算.利用开发的编码对低杂波在托卡马克等离子体中的吸收和驱动效率进行了Fokker-Planck计算,考查了环形托卡马克装置的纵横比对波功率沉积和电流驱动效率产生的作用.研究表明,俘获电子效应对低杂波电流驱动的影响与波驱动的功率谱结构有关.俘获电子的平行速度较低,优化的功率谱可以在共振的电子数和俘获电子之间取得折中.俘获电子效应可以使低杂波电流驱动效率减小30%.
关键词:
Fokker-Planck方程
俘获电子效应
低杂波电流驱动 相似文献
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给出了计算共振区平均中子俘获r能谱的方案。主要考虑了三种反应机制:统计过程、位阱俘获与复弹性道中的俘获脚。具体计算了3s共振区几个核素51V,52Cr,55Mn的热中子俘获r能谱和r光子多重数。结果表明,包括了复弹性道中的俘获这一过程后,理论与实验的符合得到明显的改善,特别是对能谱的高能端。 相似文献
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随着压电晶体材料的迅速发展, 基于压电效应的能量采集系统是俘获环境中的宽带随机振动能量的一种有效途径. 研究了有限宽带随机激励作用下, 磁斥力双稳态压电俘能系统的相干共振俘能机理, 并进行了实验验证. 运用Euler-Maruyama方法求解了随机非线性压电振动耦合方程, 比较分析了相干共振发生前后系统的动力学特性和俘能效率, 然后基于Kramers逃逸速率解释了相干共振. 最后的随机振动实验结果验证了双稳态压电俘能系统的相干共振俘能机理. 并且观察到: 当相干共振发生时, 系统会在两个势能阱之间剧烈运动, 此时宽带随机振动能量会被转化为大幅值窄带低频振动响应, 从而极大地提高了宽带随机振动能量的俘获效率. 相似文献
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《Infrared physics》1993,34(6):601-605
Using the well-known Beattie-Landsberg expression for Auger 1 lifetime and the “effective” Auger energy gap (EgA), we obtained a simple approximative expression for determination of the Auger 1 lifetime. We also obtained a formula for the electron concentration above which the effects of degeneration are significant. 相似文献
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The main mechanisms for the Auger recombination of nonequilibrium carriers in semiconductor quantum-well heterostructures
are investigated. It is shown for the first time that there are three fundamentally different Auger recombination mechanisms
in quantum wells: 1) a threshold-free mechanism, 2) a quasithreshold mechanism, and 3) a threshold mechanism. The rate of
the threshold-free process has a weak temperature dependence. The rate of the quasithreshold Auger process exhibits an exponential
temperature dependence. However, the threshold energy depends significantly on the quantum-well width and is close to zero
for narrow quantum wells. It is shown that the threshold-free and quasithreshold processes are dominant in fairly narrow quantum
wells, while the quasithreshold and threshold Auger processes are dominant in wide quantum wells. The limiting transition
to a three-dimensional Auger process is accomplished for a quantum-well width tending to infinity. The value of the critical
quantum-well width, at which the quasithreshold and threshold Auger processes combine to form a single three-dimensional Auger
recombination process, is found.
Zh. éksp. Teor. Fiz. 113, 1491–1521 (April 1998) 相似文献
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E. B. Dogonkin G. G. Zegrya A. S. Polkovnikov 《Journal of Experimental and Theoretical Physics》2000,90(2):378-388
An analysis is made of mechanisms for Auger recombination of nonequilibrium carriers in cylindrical quantum wires. It is shown that two different Auger recombination mechanisms take place in these wires: a quasi-threshold and a nonthreshold mechanism. Both mechanisms are associated with the presence of heterobarriers but are of a different nature. The quasi-threshold mechanism is attributed to the spatial confinement of the carrier wave functions to the region of the quantum wire and in this case the quasi-momentum conservation law is violated and the Auger recombination process is intensified. As the radius of the wire increases, the quasi-threshold Auger recombination process goes over to a threshold process. The nonthreshold mechanism is caused by the scattering of an electron (hole) at the heterojunction; the rate of this nonthreshold Auger recombination tends to zero in the limit of an infinite-radius wire. 相似文献
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Viefhaus J Cvejanović S Langer B Lischke T Prümper G Rolles D Golovin AV Grum-Grzhimailo AN Kabachnik NM Becker U 《Physical review letters》2004,92(8):083001
We have observed the direct L(2,3)MMM double Auger transition after photoionization of the 2p shell of argon by angle-resolved electron-electron coincidence spectroscopy. The process is responsible for about 20% of the observed Auger electron intensity. In contrast to the normal Auger lines, the spectra in double Auger decay show a continuous intensity distribution. The energy and angular distributions of the emitted electrons allow one to obtain information on the electron correlations giving rise to the double Auger process as well as the symmetry of the associated two-electron continuum state. 相似文献
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Ranitovic P Tong XM Hogle CW Zhou X Liu Y Toshima N Murnane MM Kapteyn HC 《Physical review letters》2011,106(5):053002
In rare-gas atoms, Auger decay in which an inner-valence shell ns hole is filled is not energetically allowed. However, in the presence of a strong laser field, a new laser-enabled Auger decay channel can open up to increase the double-ionization yield. This process is efficient at high laser intensities, where an ns hole can be filled within a few femtoseconds of its creation. This novel laser-enabled Auger decay process is of fundamental importance for controlling electron dynamics in atoms, molecules, and materials. 相似文献
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Auger-like exciton-exciton annihilation in isolated single-walled carbon nanotubes (SWNTs) has been studied by femtosecond transient absorption spectroscopy. We observe a quantization of the Auger recombination process and extract dynamics for 2 and 3 electron-hole pair excited states. We further demonstrate that Auger recombination in SWNTs is a two-particle process involving strongly bound excitons and not a three-particle Auger process involving unbound electrons and holes. We thus provide explicit experimental evidence for one-dimensional discrete excitons in SWNTs. 相似文献
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Penent F Lablanquie P Palaudoux J Andric L Gamblin G Hikosaka Y Ito K Carniato S 《Physical review letters》2011,106(10):103002
We present an experimental and theoretical study of triply charged hydrogen bromide ions formed by photoionization of the inner 3d shell of Br. The experimental results, obtained by detecting the 3d photoelectron in coincidence with the two subsequent Auger electrons, are analyzed using calculated potential energy curves of HBr3+. The competition between the short-range chemical binding potential and the Coulomb repulsion in the dissociative process is shown. Two different mechanisms are observed for double Auger decay: one, a direct process with simultaneous ejection of two Auger electrons to final HBr3+ ionic states and the other, a cascade process involving double Auger decay characterized by the autoionization of Br*+ ion subsequent to the HBr2+ fragmentation. 相似文献
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Microscopic calculation of the probability of Auger recombination of charge carriers localized in a semiconducting quantum dot (QD) is carried out. It is shown that two mechanism of Auger recombination (nonthreshold and quasi-threshold) operate in the QD. The nonthreshold Auger recombination mechanism is associated with scattering of a quasimomentum from a heterobarrier, while the quasi-threshold mechanism is connected with spatial confinement of the wave functions of charge carriers to the QD region; scattering of carriers occurs at the short-range Coulomb potential. Both mechanisms lead to a substantial enhancement of Auger recombination at the QD as compared to a homogeneous semiconductor. A detailed analysis of the dependence of Auger recombination coefficient on the temperature and QD parameters is carried out. It is shown that the nonthreshold Auger recombination process dominates at low temperatures, while the quasi-threshold mechanism prevails at high temperatures. The dependence of the Auger recombination coefficient on the QD radius experiences noticeable changes as compared to quantum wells and quantum filaments. 相似文献
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A. Haug 《Solid State Communications》1977,22(8):537-539
Phonon-assisted Auger recombination is studied in strongly degenerate semiconductors since normal Auger recombination is negligible in this case. The results are discussed in connection with an electron-hole-plasma. There are some indications that phonon-assisted Auger recombination is an important process in this case. 相似文献
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S. Martin J. Bernard L. Chen A. Denis J. Désesquelles 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2000,12(1):27-32
Resonant excitation or resonant electron scattering is a two step process in which Auger rates are involved in both steps.
First an electron is captured into a bound state and a bound electron is excited (inverse Auger effect). Then an Auger transition
leads to the emission of the electron from the ion. The corresponding cross-sections are very sensitive to the Auger rates
and allow a detailed study of the Breit interaction which is a current-current contribution to the static electron-electron
interaction. The contribution of the Breit interaction to the cross-section of resonant excitation on hydrogen-like uranium
ions is discussed and shown that it is roughly twice as large as in the case of dielectronic recombination.
Received 4 August 1999 and Received in final form 29 September 1999 相似文献