Magnetic flux ropes of solar origin and helicity conservation

This dissertation contains a study of magnetic flux ropes of solar origin including those found on the Sun as well as those ejected from the Sun into the interplanetary space. Conservation of magnetic helicity in the flux ropes restricts the nature of their evolution and provides many insights into their behavior.; In chapter 3 a filament is modeled as H{dollar}alpha{dollar} absorbing material sitting in the lower portions of the helical field lines of a flux rope that emerges fully formed from below the solar surface. Smaller flux ropes are forced to accumulate in neutral channels, in the inverse polarity configuration, where they bundle together to form the giant filament flux ropes. This scenario along with the observed hemispherical segregation of magnetic helicity, explains the difference between high latitude quiescent filaments and low latitude active region filaments. A filament oscillation model predicts time periods between 10 and 100 minutes in agreement with observations of Bashkirtsev and Mashnich (1984).; In chapter 4 a flux rope model for interplanetary magnetic clouds, is developed that uses conservation of magnetic helicity, flux and mass to explain their evolution and heating. An expanding cloud continuously loses its magnetic energy. Even after accounting for the mechanical losses about 60% of the lost magnetic energy is available to dissipate into heat. The total plasma beta in a cloud approaches a constant value between 0.39 and 0.52. Derived expressions (scaling laws) for the magnetic field strength, radius, density, temperature, and the slope of the plasma velocity profile as functions of distance from the Sun, are in agreement with the cloud data obtained between 0.3 and 4 AU.; In chapter 5 the case of solar wind consisting of numerous flux ropes of various sizes and strengths is considered to obtain scaling laws that are in agreement with the observations of Totten et al. (1995).; In chapter 6 the evidence for kink instability in sigmoidal flux ropes seen in the X-ray pictures of the solar corona is discussed.; The appendix contains an account of my work for the Flare Genesis Experiment.