Heating And Acceleration Of Ions By Alfven Waves Via Nonresonant Interactions

The heating of solar corona and the acceleration of high speed solar wind is the long standing problem in the solar physics and space physics. After the discussion of several decades, with more and more observational data, it is believed that Alfven waves play a key role in solving this problem. There are two approaches in the research of the effect of Alfven waves in solar corona and solar wind. The first approach is the magnetohydrodynamic method in the macro-scale. The other approach is the kinetic method in the micro-scale. This dissertation concentrates on the micro-scale that how the Alfven waves interact with the charge particles, exchange energy with the plasma, heat and accelerate the solar corona and solar wind effectively. In the micro-scale, the kinetic process that the Alfven waves exchange energy with the ions can be divided into the cyclotron resonance interaction process and the non-resonant interaction process. We focus on the non-resonant heating and the stochastic heating that do not depend on the linear cyclotron resonant condition.We found that newborn ions can get irreversible heating from turbulent Alfven waves, by investigating the different manifestations of the background ions and the newborn ions in the non-resonant heating. Considering the ionization and recombination process in the plasma, we estimated the heating rate of ions due to non-resonant interaction with turbulent Alfven waves, and found that such a heating process could be significant in the upper chromosphere and transition region of the sun.We investigated the interactions between the low-frequency Alfven waves and minor ions in solar wind, based on the mechanism of non-resonant heating and stochastic heating, by means of the test-particle simulation. We found that although the low-frequency waves cannot heat the ions through linear cyclotron resonant process, they can heat the ions effectively via the pitch angle scattering process, when the wave amplitude exceeds some threshold condition for stochasticity, the minor ions will be non-resonantly picked up by Alfven waves. During this process, both the non-resonant heating and the stochastic heating play key roles. After been picked up, the time-asymptotic kinetic temperature and the bulk speed of the minor ions were independent of the wave amplitude, and they always approaches the value dictated by the Alfven speed. Different kinds of ions perform similar in this process, while the speeds of been picked up are different. The thermal speed and the bulk speed of different kinds of ions with different charge-to-mass ratios will be similar, and are independent of the charge and mass of the ionsWe studied the stochastic heating and acceleration process of the heavy ions by means of test-particle simulation while treating the heavy ions as diagnostic tracers, using the observational normalized power of magnetic transverse fluctuations in solar wind. The results of the simulation are basically consistent with the kinetic properties of O5+ions and helium ions observed in the solar corona and solar wind, respectively. According to the observation, both high-frequency waves (far below the ion gyro-frequency) and low-frequency waves (near the ion gyro-frequency) exist in the solar wind, although the energy mainly focuses on the low-frequency waves. We adopt the similar wave spectrum in the simulation and found that both the low frequency waves and high frequency waves play key roles for the stochastic heating and acceleration. The high frequency waves are important because they can randomize the ion orbit through resonant wave-particle interactions. The low frequency wave is important because they can farther pitch-angle scatter the ions along the energy conservation sphere-shell in the wave frame due to their large amplitude.According to the results of this dissertation, the pick-up of heavy ions by turbulent Alfven-cyclotron waves via stochastic heating and acceleration may be a universally happening process in the solar corona and solar wind. In the coronal, minor ions may have not been fully picked up. Thus, the minor ions are with highly anisotropic temperature, and flow faster than protons by a fraction of the local Alfven speed. In the interplanetary space, minors may be nearly full picked up, so the minor ion temperature is proportional to their mass, and flow faster than protons by about the local Alfven speed. The low frequency waves are the main part of the Alfven-cyclotron wave spectrum observed in situ, while the high frequency waves only occupy little energy of the whole spectrum. We consider that both waves are important for the pick-up of minor ions by theses waves.