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Kinetic Physics of the Solar Corona and Solar Wind
Marsch Eckart
Living Reviews in Solar Physics , 2006,
Abstract: Kinetic plasma physics of the solar corona and solar wind are reviewed with emphasis on the theoretical understanding of the in situ measurements of solar wind particles and waves, as well as on the remote-sensing observations of the solar corona made by means of ultraviolet spectroscopy and imaging. In order to explain coronal and interplanetary heating, the microphysics of the dissipation of various forms of mechanical, electric and magnetic energy at small scales (e.g., contained in plasma waves, turbulences or non-uniform flows) must be addressed. We therefore scrutinise the basic assumptions underlying the classical transport theory and the related collisional heating rates, and also describe alternatives associated with wave-particle interactions. We elucidate the kinetic aspects of heating the solar corona and interplanetary plasma through Landau- and cyclotron-resonant damping of plasma waves, and analyse in detail wave absorption and micro instabilities. Important aspects (virtues and limitations) of fluid models, either single- and multi-species or magnetohydrodynamic and multi-moment models, for coronal heating and solar wind acceleration are critically discussed. Also, kinetic model results which were recently obtained by numerically solving the Vlasov–Boltzmann equation in a coronal funnel and hole are presented. Promising areas and perspectives for future research are outlined finally.
The Study and Investigation of Electron Trajectories in Free Electron Laser with Realizable Helical Wiggler and Ion Channel Guiding: A Computational Study  [PDF]
Alireza Heidari, Mohammadali Ghorbani
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.33039
Abstract: The following article has been retracted due to the investigation of complaints received against it. Mr. Mohammadali Ghorbani (corresponding author and also the last author) cheated the author’s name: Alireza Heidari. The scientific community takes a very strong view on this matter and we treat all unethical behavior such as plagiarism seriously. This paper published in Vol.3 No.3, 278-281, 2012, has been removed from this site.
A Physical Explanation for the Formation of Auroras  [PDF]
Weihong Qian
Journal of Modern Physics (JMP) , 2023, DOI: 10.4236/jmp.2023.143018
Abstract: What mechanism causes the symmetrical distribution of two oval-ring auroras approximately around the geomagnetic poles but uneven brightness distribution of them? To answer this question, we firstly describe the charged particles like electrons or protons emitted from the Sun and the magnetic ions formed in the Earth’s atmosphere. Then, the interaction dynamics of two-type particles between electron and ion is given under the non-relativistic limit. Finally, under the relativistic frame, auroras deduced are higher energy density formed by the orthogonal interaction of solar charged particles and geomagnetic ions in the narrow regions centered on the upper geomagnetic poles. The physical nature of ideal oval-ring auroras with uneven brightness distribution is an optical phenomenon that occurs when solar charged particles collide orthogonally with ions and the magnetic axis inclines to the solar radiation. For actual aurora distribution, the impact of multiple factors is discussed. Therefore, the aurora is a natural illustration of an orthogonal collider in the Earth’s upper atmosphere.
Skewed superstatistical distributions from a Langevin and Fokker-Planck approach
Erik Van Der Straeten,Christian Beck
Chinese Science Bulletin , 2011, DOI: 10.1007/s11434-011-4700-z
Abstract: The superstatistics concept is a useful statistical method to describe inhomogeneous complex systems for which a system parameter β fluctuates on a large spatio-temporal scale. In this paper we analyze a measured time series of wind speed fluctuations and extract the superstatistical distribution function f(β) directly from the data. We construct suitable Langevin and Fokker-Planck models with a position dependent β-field and show that they reduce to standard type of superstatistics in the overdamped limit.
Comparison of High Field Electron Transport in GaAs, InAs and In0.3Ga0.7As  [PDF]
B. Bouazza, A. Guen-Bouazza, C. Sayah, N. E. Chabane-Sari
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.44A012
Abstract:

An ensemble Monte Carlosimulation is used to compare high field electron transport in bulk GaAs, InAs and In0.3Ga0.7As. In particular, velocity overshoot and electron transit times are examined. We find the steady state velocity of the electrons is the most important factor determining transit time over distances longer then 0.2 μm. Over shorter distances velocity overshoot effects in InAs and In0.3Ga0.7 As at high fields are comparable to those in GaAs. We estimate the minimum transit time across a 1 μm InAs sample to be about 4.2 ps. Similar calculations for In0.3Ga0.7As yield 6 ps (for GaAs yield 10 ps). Calculations are made using a nonparabolic effective mass energy band model, Monte Carlo simulation that includes all of the major scattering mechanisms. The band parameters used in the simulation are extracted from optimized pseudopotential band calculations to ensure excellent agreement with experimental information and ab initio band models.

Steady-State and Transient Electron Transport within Bulk InAs, InP and GaAs: An Updated Semiclassical Three-Valley Monte Carlo Simulation Analysis  [PDF]
A. Guen-Bouazza, C. Sayah, B. Bouazza, N. E. Chabane-Sari
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.45089
Abstract:

An ensemble Monte Carlosimulation is used to compare high field electron transport in bulk InAs, InP and GaAs. In particular, velocity overshoot and electron transit times are examined. For all materials, we find that electron velocity overshoot only occurs when the electric field is increased to a value above a certain critical field, unique to each material. This critical field is strongly dependent on the material, about 3 kV/cm for InAs, 10 kV/cm for InP and 5 kV/cm for the case of GaAs, We find that InAs exhibits the highest peak overshoot velocity and that this velocity overshoot lasts over the longest distances when compared with GaAs and InP. Finally, we estimate the minimum transit time across a 1 μm InAs sample to be about 2 ps. Similar calculations for InP and GaAs yield 6.6 and 5.4 ps, respectively. We find that the optimal cutoff frequency for an ideal InAs based device ranges from around 79 GHz when the device thickness is set to 1 μm. We thus suggest that indium arsenide offers great promise for future high-speed device applications. The steady-state and transient velocity overshoot characteristics are in fair agreement with other recent calculations.

Auger Spectra and Different Ionic Charges Following 3s, 3p and 3d Sub-Shells Photoionization of Kr Atoms
Yehia A. Lotfy,Adel M. El-Shemi
Symmetry, Integrability and Geometry : Methods and Applications , 2006,
Abstract: The decay of inner-shell vacancy in an atom through radiative and non-radiative transitions leads to final charged ions. The de-excitation decay of 3s, 3p and 3d vacancies in Kr atoms are calculated using Monte-Carlo simulation method. The vacancy cascade pathway resulted from the de-excitation decay of deep core hole in 3s subshell in Kr atoms is discussed. The generation of spectator vacancies during the vacancy cascade development gives rise to Auger satellite spectra. The last transitions of the de-excitation decay of 3s, 3p and 3d holes lead to specific charged ions. Dirac-Fock-Slater wave functions are adapted to calculate radiative and non-radiative transition probabilities. The intensity of Kr^{4+} ions are high for 3s hole state, whereas Kr^{3+} and Kr^{2+} ions have highest intensities for 3p and 3d hole states, respectively. The present results of ion charge state distributions agree well with the experimental data.
Two-Dimensional Lithium-Ion Battery Modeling with Electrolyte and Cathode Extensions  [PDF]
Glyn F. Kennell, Richard W. Evitts
Advances in Chemical Engineering and Science (ACES) , 2012, DOI: 10.4236/aces.2012.24052
Abstract: A two-dimensional model for transport and the coupled electric field is applied to simulate a charging lithium-ion cell and investigate the effects of lithium concentration gradients within electrodes on cell performance. The lithium concentration gradients within electrodes are affected by the cell geometry. Two different geometries are investigated: extending the length of the electrolyte past the edges of the electrodes and extending the length of the cathode past the edge of the anode. It is found that the electrolyte extension has little impact on the behavior of the electrodes, although it does increase the effective conductivity of the electrolyte in the edge region. However, the extension of the cathode past the edge of the anode, and the possibility for electrochemical reactions on the flooded electrode edges, are both found to impact the concentration gradients of lithium in electrodes and the current distribution within the electrolyte during charging. It is found that concentration gradients of lithium within electrodes may have stronger impacts on electrolytic current distributions, depending on the level of completeness of cell charge. This is because very different gradients of electric potential are expected from similar electrode gradients of lithium concentrations at different levels of cell charge, especially for the LixC6 cathode investigated in this study. This leads to the prediction of significant electric potential gradients along the electrolyte length during early cell charging, and a reduced risk of lithium deposition on the cathode edge during later cell charging, as seen experimentally by others.
Ion Nonthermality Induced Nonlinear Dust Acoustic Wave Propagation in a Complex Plasma in Presence of Weak Secondary Electron Emission from Dust Grains  [PDF]
Subrata Bhakta, Susmita Sarkar
Journal of Modern Physics (JMP) , 2018, DOI: 10.4236/jmp.2018.95059
Abstract: In this paper we have investigated the effect of ion nonthermality on nonlinear dust acoustic wave propagation in a complex plasma in presence of weak secondary electron emission from dust grains. Equilibrium dust charge in this case is negative. Dusty plasma under our consideration consists of inertialess nonthermal ions, Boltzman distributed primary and secondary electrons and negatively charged inertial dust grains. Both adiabatic and nonadiabatic dust charge variations have been taken into account. Our analysis shows that in case of adiabatic dust charge variation, at a fixed non-zero ion nonthermality increasing secondary electron emission decreases amplitude and increases width of the rarefied dust acoustic soliton whereas for a fixed secondary electron yield increasing ion nonthermality increases amplitude and decreases width of such rarefied dust acoustic soliton. Thus shape of the soliton may be retained if strength of both the secondary electron yield and the ion nonthermality are increased. Nonadiabatic dust charge variation shows that, at fixed non-zero ion nonthermality, increasing secondary electron emission suppresses oscillation of oscillatory dust acoustic shock at weak nonadiabaticity and pronounces monotonicity of monotonic dust acoustic shock at strong nonadiabaticity. On the other hand at a fixed value of the secondary electron yield, increasing ion nonthermality enhances oscillation of oscillatory dust acoustic shock at weak nonadiabaticity and reduces monotonicity of monotonic dust acoustic shock at strong nonadiabaticity. Thus nature of dust acoustic shock may also remain unchanged if both secondary electron yield and ion nonthermality are increased.
Non-Linear Ion-Acoustic Solitary Waves in Electron-Positron-Ion Plasma with Non-Thermal Electrons  [PDF]
S. K. Anguma, I. Habumugisha, L. Nazziwa, E. Jurua, N. Noreen
Journal of Modern Physics (JMP) , 2017, DOI: 10.4236/jmp.2017.86055
Abstract: Ion-acoustic solitary (IAS) waves in electron-positron-ion (e-p-i) plasma have been of interest to many researchers probably due to their relevance in understanding the Universe. However, the study of non-linear ion-acoustic waves in e-p-i plasma with non-thermal electrons has not been adequately studied. A theoretical investigation on non-linear IAS waves in e-p-i plasma comprising of warm inertial adiabatic fluid ions and electrons that are kappa distributed, and Boltzman distributed positron is presented here using the Sagdeev potential technique. It was found that existence domains of finite amplitude IAS waves were confined within the limits of minimum and maximum Mach numbers with varying k values. For lower values of k, the amplitude of the solitary electrostatic potential structures increased as the width decreased, while for high values, the potential amplitude decreased as the width of the solitary structure increased.
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