Cosmochemistry of the rare earth elements: meteorite studies.

Rare-earth abundances in chondritic meteorites

A review is presented of the models of magnetic field line merging defined as the process whereby plasma flows across a surface which separates regions including topologically different magnetic field lines. The models examined are characterized by uniform and antiparallel external magnetic fields. An attempt is made to simplify the presentation of the models, to clarify some doubtful mathematical points, or to extend the results to a different range of physical parameters. The models are described from a hydromagnetic point of view, with the configuration in any given case being determined by the boundary conditions. It is shown that the models developed by Sweet (1958), Parker (1957, 1963), Petschek (1964), Sonnerup (1970), and by Yeh and Axford (1970) are basically consistent, describing different aspects of the same problem; however, there is not a single model that would account for all the cases considered. The singular models and the compressible similarity models are physically not feasible.

Theoretical models of magnetic field line merging

Part I. Astronomical Background: 1. High energy astrophysics - an introduction 2. The stars and stellar evolution 3. The galaxies 4. Clusters of galaxies Part II. Physical Processes: 5. Ionisation losses 6. Radiation of accelerated charged particles and bremsstrahlung of electrons 7. The dynamics of charged particles in magnetic fields 8. Synchrotron radiation 9. Interactions of high energy photons 10. Nuclear interactions 11. Aspects of plasma physics and magnetohydrodynamics Part III. High Energy Astrophysics in our Galaxy: 12. Interstellar gas and magnetic fields 13. Dead stars 14. Accretion power in astrophysics 15. Cosmic rays 16. The origin of cosmic rays in our galaxy 17. The acceleration of high energy particles Part IV. Extragalactic High Energy Astrophysics: 18. Active galaxies 19. Black holes in the nuclei of galaxies 20. The vicinity of the black hole 21. Extragalactic radio sources 22. Compact extragalactic sources and superluminal motions 23. Cosmological aspects of high energy astrophysics Appendix References Index.

High Energy Astrophysics

A theoretical model of flare which explains observed quantities in Ha, EUV, soft X-ray and flare-associated solar wind is presented. It is assumed that large mass observed in the soft X-ray flare and the solar wind comes from the chromosphere by the process like evaporation while flare is in progress. From mass and pressure balance in the chromosphere and the corona, the high temperature in the soft X-ray flare is shown to be attained by the larger mass loss to the solar wind compared with the mass remained in the corona, in accord with observations. The total energy of 10 a2 erg, the electron density of l013'5 cm -a in Hc~ flare, the temperature of the X-ray flare of 107.3K and the time to attain maximum Ha brightness (600 s) are derived consistent with observations. It is shown that the top height of the Ha flare is located about 1000 km lower than that of the active chromosphere because of evaporation. So-called limb flares are assigned to either post-flare loops, surges or rising prominences. The observed small thickness of the Ha flare is interpreted by free streaming and/or heat conduction. Applications are suggested to explain the maximum temperature of a coronal condensation and the formation of quiescent prominences.

THEORETICAL MODEL OF FLARES AND PROMINENCES I: Evaporating Flare Model

IF a conducting liquid is placed in a constant magnetic field, every motion of the liquid gives rise to an E. M. F. which produces electric currents. Owing to the magnetic field, these currents give mechanical forces which change the state of motion of the liquid. Thus a kind of combined electromagnetic-hydro-dynamic wave is produced which, so far as I know, has as yet attracted no attention.

Existence of Electromagnetic-Hydrodynamic Waves

Currents in the solar atmosphere and a theory of solar flares

According to Biermann's theory the repulsive force in comet tails is due to a corpuscular radiation from the sun. It is shown that some of the difficulties of this theory can be overcome if the assumed radiation consists of beams with a frozen-in magnetic field of the same type as required in the electric field theory of magnetic storms and aurorae. The interaction between such a beam and the head of the comet produces an amplified magnetic field which determines the shape of the tail. The high accelerations, which have been observed in the tails may be due to electromagnetic forces. DOI: 10.1111/j.2153-3490.1957.tb01855.x

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.2153-3490.1957.tb01855.x

On the Theory of Comet Tails

: A theory of the origin of the solar system is discussed, including introduction and general principles, accretion of planets, partial corotation of a magnetized plasma, and the structure of the Saturnian rings. (Author)

On the origin of the solar system

The origin and evolution of the solar system are analyzed. Physical processes are first discussed, followed by experimental studies of plasma-solid reactions and chemical and mineralogical analyses of meteorites and lunar and terrestrial samples.

Hannes Alfvén

Papers

Existence of Electromagnetic-Hydrodynamic Waves

Currents in the solar atmosphere and a theory of solar flares

On the Theory of Comet Tails

On the origin of the solar system

Evolution of the Solar System