Particle Acceleration and Kinematics in Solar Flares

ISBN-13: 9781402007255 / Angielski / Twarda / 2002 / 228 str.

Markus J. Aschwanden

Opis

Over the last decade we entered a new exploration phase of solar flare physics, equipped with powerful spacecraft such as Yohkoh, SoHO, and TRACE that pro vide us detail-rich and high-resolution images of solar flares in soft X-rays, hard X -rays, and extreme-ultraviolet wavelengths. Moreover, the large-area and high sensitivity detectors on the Compton GRO spacecraft recorded an unprecedented number of high-energy photons from solar flares that surpasses all detected high energy sources taken together from the rest of the universe, for which CGRO was mainly designed to explore. However, morphological descriptions of these beau tiful pictures and statistical catalogs of these huge archives of solar data would not convey us much understanding of the underlying physics, if we would not set out to quantify physical parameters from these data and would not subject these measurements to theoretical models. Historically, there has always been an unsatisfactory gap between traditional astronomy that dutifully describes the mor phology of observations, and the newer approach of astrophysics, which starts with physical concepts from first principles and analyzes astronomical data with the goal to confirm or disprove theoretical models. In this review we attempt to bridge this yawning gap and aim to present the recent developments in solar flare high-energy physics from a physical point of view, structuring the observations and analysis results according to physical processes, such as particle acceleration, propagation, energy loss, kinematics, and radiation signatures."

Spis treści

1: Introduction. 2: Magnetic Topology of Acceleration Regions. 2.1. Bipolar Reconnection Models. 2.2. Tripolar Reconnection Models.2.3. Quadrupolar Reconnection Models. 2.4. Spine and Fan Reconnection Models. 3: Geometry of Acceleration Regions. 3.1. Magnetic Topology Constraints on the Acceleration Region. 3.2. Direct Hard X-Ray Detection of the Acceleration Region. 3.3.Time-of-Flight Localization of the Acceleration Region. 3.4. Conjugate Footpoint Constraints. 3.5. Remote Footpoint Delays. 3.6. Bi-Directional Electron Beams. 3.7. Hard X-Ray and Radio-Coincident Electron Beams. 3.8. Electron Density in Acceleration Sites. 4: Dynamics of Acceleration Region. 4.1. Dynamics of Flare Triggers and Drivers. 4.2. Dynamics of Magnetic Reconnection. 4.3. Dynamics Inferred from Fast Time Structures. 4.4. Dynamics Inferred from Spatio-Temporal Fragmentation. 4.5. Dynamics Inferred from Spatial Evolution. 5: Accelerating Electromagnetic Fields and Waves. 5.1. Electric DC Field Acceleration. 5.2.Stochastic Acceleration. 5.3. Shock Acceleration. 6: Particle Kinematics. 6.1. Kinematics of Relativistic Particles. 6.2. Kinematics of Particle Acceleration. 6.3. Kinematics of Particle Propagation. 6.4. Kinematics of Combined Acceleration and Propagation. 6.5. Kinematics of Particle Injection. 6.6. Kinematics of Particle Trapping. 6.7. Kinematics of Particle Precipitation. 6.8. Kinematics of Particle Energy Loss. 7: Gamma Ray Emission. 7.1. Gamma Ray Emission Processes. 7.2.Acceleration and Propagation of Protons. 7.3. Inverse Bremsstrahlung of Protons. 7.4.Relative Proton-to-Electron Acceleration Ratios. 7.5. Long-Term Trapping of High-Energy Particles. 7.6. Gamma-rays from Behind-the-Limb Flares. 7.7. Pitch-Angle Distribution of High-Energy Particles. 7.8. Interplanetary High-Energy Particles. 8: Hard X-Ray Emission. 8.1. Hard X-Ray Bremsstrahlung Emission. 8.2. Time-Dependent Hard X-Ray Spectra. 8.3. Hard X-Ray Spectra. 8.4. Spatial Structure of Hard X-Ray Sources.9: Radio Emission. 9.1 Radio Diagnostic of Electron Acceleration. 9.2. Radio Diagnostic of Electron Propagation. 9.3. Radio Diagnostic of Electron Trapping. 10: Conclusions. References.