Field In Solar Atmosphere Research Articles

Coulomb Collisions and Electron Acceleration in Sub-Dreicer Electric Fields of the Corona and Chromosphere

Based on single-particle approximation, the peculiarities of electron acceleration by the sub-Dreicer electric field in solar atmosphere have been considered. The elastic and inelastic collisions of fast electrons with hydrogen atoms have been taken into account within the Born approximation. The rate of energy gain by accelerated electrons is inversely proportional to the mean free path of the thermal particles. Electron acceleration can be more effective in the transition region and chromosphere than in the corona. Chromospheric electrons can achieve several hundred keV energy at distances of a few tens of kilometers.

The magnetic field in the solar atmosphere

This publication provides an overview of magnetic fields in the solar atmosphere with the focus lying on the corona. The solar magnetic field couples the solar interior with the visible surface of the Sun and with its atmosphere. It is also responsible for all solar activity in its numerous manifestations. Thus, dynamic phenomena such as coronal mass ejections and flares are magnetically driven. In addition, the field also plays a crucial role in heating the solar chromosphere and corona as well as in accelerating the solar wind. Our main emphasis is the magnetic field in the upper solar atmosphere so that photospheric and chromospheric magnetic structures are mainly discussed where relevant for higher solar layers. Also, the discussion of the solar atmosphere and activity is limited to those topics of direct relevance to the magnetic field. After giving a brief overview about the solar magnetic field in general and its global structure, we discuss in more detail the magnetic field in active regions, the quiet Sun and coronal holes.

Observations of magnetic and kinetic helicity proxies

AbstractThe helicity is important to present the basic topological configuration of magnetic field in solar atmosphere. The distribution of magnetic helicity in solar atmosphere is presented by means of the observational (vector) magnetograms. As the kinetic helicity in the solar subatmosphere can be inferred from the velocity field based on the technique of the helioseismology and used to compare with the magnetic helicity in the solar atmosphere, the observational helicities provide the important chance for the confirmation on the generation of magnetic fields in the subatmosphere and solar dynamo models also. In this paper, we present the observational magnetic and kinetic helicity in solar active regions and corresponding questions, except the relationship with solar eruptive phenomena.

Extracting information on the vector magnetic field in solar atmosphere

Extracting information on the vector magnetic field in solar atmosphere

Large-scale electric fields in post-flare loops

As the electrical conductivity along the magnetic field in solar atmosphere is large, parallel electric fields have been neglected in most investigations. We will first demonstrate their importance for post-flare loops, and then introduce a model for them which takes into account the effect of parallel electric fields. The electric field calculated from the model is consistent with the electric field observed by Foukal et al. (1983).