scholarly journals Magnetic fields, plasmas, and coronal holes: The inner solar system

1979 ◽  
Vol 23 (2) ◽  
Author(s):  
L.F. Burlaga
2009 ◽  
Vol 152 (1-4) ◽  
pp. 391-421 ◽  
Author(s):  
Joachim Saur ◽  
Fritz M. Neubauer ◽  
Karl-Heinz Glassmeier

1991 ◽  
Vol 144 ◽  
pp. 267-280 ◽  
Author(s):  
Rainer Beck

Spiral galaxies host interstellar magnetic fields of 4-15 μG total strength. A significant fraction of the field lines shows large-scale structures. At face-on or moderately inclined view, the field lines run generally parallel to the spiral arms, either with uniform direction with respect to azimuthal angle (axisymmetric spiral, ASS), with one reversal along azimuthal angle (bisymmetric spiral, BSS), or with spiral orientation without dominating direction.At edge-on view, the field is concentrated in a thin disk, often surrounded by a thick radio disk with field lines mostly parallel to the plane, similar to the quadrupole-type dynamo field. Radio polarization data from NGC891 indicate that the thermal gas seen in Hα is responsible for Faraday depolarization. The required scaleheight of the field of ~4 kpc is comparable to the value expected in case of energy equipartition between magnetic fields and cosmic rays. The interacting edge-on galaxy NGC 4631 shows a much larger radio halo with field lines perpendicular to the disk, possibly driven by a strong galactic wind or the result of a dipole-type halo field.Field lines bending out of the plane are also visible in face-on galaxies as regions with high rotation measures and low star-formation activity. The resemblance to the phenomenon of the solar corona suggests to call them “galactic coronal holes”.


Author(s):  
Václav Bumba ◽  
Miroslav Klvaňa ◽  
Július Sýkora

2019 ◽  
Vol 15 (S354) ◽  
pp. 228-231
Author(s):  
Chia-Hsien Lin ◽  
Guan-Han Huang ◽  
Lou-Chuang Lee

AbstractCoronal holes can be identified as the darkest regions in EUV or soft X-ray images with predominantly unipolar magnetic fields (LIRs) or as the regions with open magnetic fields (OMF). Our study reveals that only 12% of OMF regions are coincident with LIRs. The aim of this study is to investigate the conditions that affect the EUV intensity of OMF regions. Our results indicate that the EUV intensity and the magnetic field expansion factor of the OMF regions are weakly positively correlated when plotted in logarithmic scale, and that the bright OMF regions are likely to locate inside or next to the regions with closed field lines. We empirically determined a linear relationship between the expansion factor and the EUV intensity. The relationship is demonstrated to improve the consistency from 12% to 23%. The results have been published in Astrophysical Journal (Huang et al. 2019).


2017 ◽  
Vol 5 (9) ◽  
pp. 145-151
Author(s):  
Samir A Hamouda ◽  
Eman A. Alsslam Alfadeel ◽  
Mohamed Belhasan Mohamed

Gravity plays a major role in the planetary formation and the development of the solar system. Gravity attraction is the essence of a power that holds and governs the universe; it makes the planets in the solar system revolve around the sun and the moons around their planets. Magnetic fields are also an important phenomenon in the solar system and beyond. Their causes are complex and have a variety of effects on their surroundings; they have become a critical tool for the exploration of solar system bodies. However, the study of the mechanisms of planets formation in the solar system is a difficult problem made more so by the inability to construct planetary-scale models for laboratory study. However, understanding the nature of the matter comprising the Solar System is crucial for understanding the mechanism that generates planetary magnetic fields and planetary gravity. In this study, a brief history about the development of planetary gravity is presented. Some data about the physical properties of planets in the solar system are presented and discussed. However, much work is still needed before the planetary gravity and planetary magnetic field processes are fully understood and full advantage be taken of the implications of both phenomena  observations.


1994 ◽  
Vol 144 ◽  
pp. 65-67 ◽  
Author(s):  
V. Bumba ◽  
M. Klvaňa ◽  
V. Rušin ◽  
M. Rybanský ◽  
G. T. Buyukliev

The photoelectric magnetograph of the Ondřejov Observatory was reconstructed in 1990 (Klvaňa and Bumba, 1994; Klvaňaet al, 1994). During 1991 and 1992, several hundred sets of measurements were obtained, mostly in line Fel 5253.47 Å. It has been found that some of the measurements are distributed very favorably around coronal holes, sometimes covering smaller parts and in a few cases even larger parts of their areas.Both 1991 and 1992 were exceptional as regards their relation to the phase of the ending solar activity cycle (No 22): while the period of the secondary cycle maximum (mainly the southern solar hemisphere) took place in 1991, the year 1992 coincided with the initial stage of its declining branch. Since the formation of coronal holes is in close relation to the dynamics of the global distribution of solar magnetic fields, we thought that before starting to investigate the detailed connections of the individual coronal holes with particular local magnetic fields, it might be interesting to study their mutual relations also on a large scale.


Author(s):  
Anton Berhulov

Subject of interstellar flights remains actual taking into account limitedness of the terrestrial resources, overpopulation of the planet, and demographic, sociopolitical and ecological problems at the planet. A constructive solution is submitted of the construction of a spacecraft moving with acceleration resting upon electromagnetic fields of the Solar system and the Galaxy. Calculation of the current intensity within the circuit and charge value at the object's useful surface necessary for the achievement of acceleration equal to 1g at arbitrary direction in the space is conducted. A method of levitation in magnetic fields of planets (superposition of magnetic fields of a star and a planet) and interplanetary space (superposition of magnetic fields of galaxies) without using the Coulomb force is proposed.


2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Vladimir N. Obridko ◽  
Bertha D. Shelting

We propose a new concept that considers the global complexes of activity as a combination of global and local fields. Traditionally, the complexes of activity have been identified from observations of active regions (ARs). Here, we show that a complex of activity comprises both (AR) and coronal holes (CHs). Our analysis is based on observations of magnetic fields of various scales, SOHO/MDI data, and UV observations of CH. The analysis has corroborated the existence of complexes of activity that involve AR and equatorial CH. Both AR and CH are embedded in an extended magnetic region dominated by the magnetic field of one sign, but not strictly unipolar. It is shown that the evolution of CH and AR is a single process. The relationship between the fields of various scales in the course of a cycle is discussed.


Sign in / Sign up

Export Citation Format

Share Document