Solar Energetic Particles


Book Description

This concise primer introduces the non-specialist reader to the physics of solar energetic particles (SEP) and systematically reviews the evidence for the two main mechanisms which lead to the so-called impulsive and gradual SEP events. More specifically, the timing of the onsets, the longitude distributions, the high-energy spectral shapes, the correlations with other solar phenomena (e.g. coronal mass ejections), as well as the all-important elemental and isotopic abundances of SEPs are investigated. Impulsive SEP events are related to magnetic reconnection in solar flares and jets. The concept of shock acceleration by scattering on self-amplified Alfvén waves is introduced, as is the evidence of reacceleration of impulsive-SEP material in the seed population accessed by the shocks in gradual events. The text then develops processes of transport of ions out to an observer. Finally, a new technique to determine the source plasma temperature in both impulsive and gradual events is demonstrated. Last but not least the role of SEP events as a radiation hazard in space is mentioned and a short discussion of the nature of the main particle telescope designs that have contributed to most of the SEP measurements is given.




Energy Conversion and Particle Acceleration in the Solar Corona


Book Description

The conversion of energy generated in the Sun's interior creates its hot corona and a wealth of dynamical phenomena such as flares and mass ejections. Based on recent significant progress in understanding magnetic reconnection and a wealth of new observations of energetic particle signatures from the sun, the present volume reviews the current theoretical and experimental status in the field. Paying attention to both the details and the broader picture, this book addresses both the experienced researcher as well as non-specialist researchers from related areas and postgraduate students.







Plasma Physics of the Local Cosmos


Book Description

Solar and space physics is the study of solar system phenomena that occur in the plasma state. Examples include sunspots, the solar wind, planetary magnetospheres, radiation belts, and the aurora. While each is a distinct phenomenon, there are commonalities among them. To help define and systematize these universal aspects of the field of space physics, the National Research Council was asked by NASA's Office of Space Science to provide a scientific assessment and strategy for the study of magnetized plasmas in the solar system. This report presents that assessment. It covers a number of important research goals for solar and space physics. The report is complementary to the NRC report, The Sun to the Earthâ€"and Beyond: A Decadal Research Strategy for Solar and Space Physics, which presents priorities and strategies for future program activities.




Fragmented Energy Release in Sun and Stars


Book Description

Magnetic energy release plays an important role in a wide variety of cosmic objects such as the Sun, stellar coronae, stellar and galactic accretion disks and pulsars. The observed radio, X-ray and gamma-ray emission often directly results from magnetic `flares', implying that these processes are spatially fragmented and of an impulsive nature. A true understanding of these processes requires a combined magnetohydrodynamical and plasma physical approach. Fragmented Energy Release in Sun and Stars: the Interface between MHD and Plasma Physics provides a comprehensive, interdisciplinary summary of magnetic energy release in the Sun and stars, in accretion disks, in pulsar magnetospheres and in laboratory plasmas. These proceedings include papers on both theoretical and observational aspects. Fragmented Energy Release in Sun and Stars: the Interface between MHD and Plasma Physics is for researchers in the fields of solar physics, stellar astrophysics and (laboratory) plasma physics and is a useful resource book for graduate level astrophysics courses.







Magnetodynamic Phenomena in the Solar Atmosphere


Book Description

These are the Proceedings of Colloquium No. 153 of the International Astro nomical Union, held at Makuhari near Tokyo on May 22 - 26, 1995, and hosted by the National Astronomical Observatory. This meeting was intended to be an interdisciplinary meeting between re searchers of solar and stellar activity, in order for them to exchange the newest information in each field. While each of these areas has seen remarkable advances in recent years, and while the researchers in each field have felt that information from the other's domain would be extremely useful in their own work, there have not been very many opportunities for intensive exchanges of information between these closely related fields. We therefore expected much from this meeting in pro viding stellar researchers with new results of research on the counterparts of their targets of research, spatially and temporarily resolved, as observed on the Sun. Likewise we hoped to provide solar researchers with new results on gigantic ver sions of their targets of research under the very different physical circumstances on other active stars. It was our greatest pleasure that we had wide attendance of experts and active researchers of both research fields from all over the world. This led to extremely interesting talks and very lively discussions, thereby stimulating the exchange of ideas across the fields.




Solar Cosmic Rays


Book Description

It turned out to be really a rare and happy occasion that we know exact1y when and how a new branch of space physics was born, namely, a physics of solar cosmic rays. It happened on February 28 and March 7, 1942 when the fIrst "cosmic ray bursts" were recorded on the Earth, and the Sun was unambiguously identifIed for the fIrst time as the source of high-velocity 10 particles with energies up to > 10 eV. Just due to such a high energy these relativistic particles have been called "solar cosmic rays" (SCR), in distinction from the "true" cosmic rays of galactic origin. Between 1942 and the beginning ofthe space era in 1957 only extremely high energy solar particle events could be occasionally recorded by cosmic ray ground-Ievel detectors and balloon borne sensors. Since then the detection techniques varied considerably and the study of SCR turned into essential part of solar and solar-terrestrial physics.