scholarly journals Earth’s magnetosphere and outer radiation belt under sub-Alfvénic solar wind

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Noé Lugaz ◽  
Charles J. Farrugia ◽  
Chia-Lin Huang ◽  
Reka M. Winslow ◽  
Harlan E. Spence ◽  
...  
Keyword(s):  
Solar Wind ◽  
Radiation Belt ◽  
Outer Radiation Belt ◽  
Earth’S Magnetosphere ◽  
Earth's Magnetosphere

scholarly journals EVIDENCE OF THE EARTH’S INNER RADIATION BELTS DURING THE LOW SOLAR AND GEOMAGNETIC ACTIVITY OBTAINED WITH THE STEP-F INSTRUMENT

2021 ◽  
Vol 26 (3) ◽  
pp. 224-238
Author(s):  
O. V. Dudnik ◽  
◽  
O. V. Yakovlev ◽  
Keyword(s):  
Geomagnetic Activity ◽  
Radiation Belt ◽  
Charged Particles ◽  
Radiation Belts ◽  
Outer Radiation Belt ◽  
Earth’S Magnetosphere ◽  
High Latitude Region ◽  
Wide Range ◽  
Earth's Magnetosphere ◽  
Particle Fluxes

Purpose: The subject of research is the spatio-temporal charged particles in the Earth’s magnetosphere outside the South Atlantic magnetic Anomaly during the 11-year cycle of solar activity minimum. The work aims at searching for and clarifying the sustained and unstable new spatial zones of enhanced subrelativistic electron fluxes at the altitudes of the low Earth orbit satellites. Design/methodology/approach: Finding and ascertainment of new radiation belts of the Earth were made by using the data analysis from the D1e channel of recording the electrons of energies of ΔEe=180–510 keV and protons of energies of ΔEp=3.5–3.7 MeV of the satellite telescope of electrons and protons (STEP-F) aboard the “CORONAS-Photon” Earth low-orbit satellite. For the analysis, the data array with the 2 s time resolution normalized onto the active area of the position-sensitive silicon matrix detector and onto the solid angle of view of the detector head of the instrument was used. Findings: A sustained structure of three electron radiation belts in the Earth’s magnetosphere was found at the low solar and geomagnetic activity in May 2009. The two belts are known since the beginning of the space age as the Van Allen radiation belts, another additional permanent layer is formed around the drift shell with the McIlwaine parameter of L = 1.65±0.05. On some days in May 2009, the new two inner radiation belts were observed simultaneously, one of those latter being recorded between the investigated sustained belt at L≈1.65 and the Van Allen inner belt at L≈2.52. Increased particle fluxes in this unstable belt have been formed with the drift shell L≈2.06±0.14. Conclusions: The new found inner radiation belts are recorded in a wide range of geographic longitudes λ, both at the ascending and descending nodes of the satellite orbit, from λ1≈150° to λ2≈290°. Separately in the Northern or in the Southern hemispheres, outside the outer edge of the outer radiation belt, at L≥7–8, there are cases of enhanced particle fl ux density in wide range of L-shells. These shells correspond to the high-latitude region of quasi-trapped energetic charged particles. Increased particle fluxes have been recorded up to the bow shock wave border of the Earth’s magnetosphere (L≈10-12). Key words: radiation belt, STEP-F instrument, electrons, magnetosphere, drift L-shell, particle flux density

scholarly journals Space Weather, SuperDARN and the Tasmanian Tiger

1997 ◽  
Vol 50 (4) ◽  
pp. 773 ◽  
Author(s):  
Raymond A. Greenwald
Keyword(s):  
Solar Wind ◽  
Electric Fields ◽  
Space Weather ◽  
Interplanetary Space ◽  
Rapid Evolution ◽  
Upper Atmosphere ◽  
Global Network ◽  
Pressure Gradients ◽  
Earth’S Magnetosphere ◽  
Earth's Magnetosphere

The plasma environment extending from the solar surface through interplanetary space to the outermost reaches of the Earth’s atmosphere and magnetic field is dynamic, often disturbed, and capable of harming humans and damaging manmade systems. Disturbances in this environment have been identified as space weather disturbances. At the present time there is growing interest in monitoring and predicting space weather disturbances. In this paper we present some of the difficulties involved in achieving this goal by comparing the processes that drive tropospheric-weather systems with those that drive space-weather systems in the upper atmosphere and ionosphere. The former are driven by pressure gradients which result from processes that heat and cool the atmosphere. The latter are driven by electric fields that result from interactions between the streams of ionised gases emerging from the Sun (solar wind) and the Earth’s magnetosphere. Although the dimensions of the Earth’s magnetosphere are vastly greater than those of tropospheric weather systems, the global space-weather response to changes in the solar wind is much more rapid than the response of tropospheric-weather systems to changing conditions. We shall demonstrate the rapid evolution of space-weather systems in the upper atmosphere through measurements with a global network of radars known as SuperDARN. We shall also describe how the SuperDARN network is evolving, including a newly funded Australian component known as the Tasman International Geospace Environmental Radar (TIGER).

scholarly journals The relativistic electron response in the outer radiation belt during magnetic storms

2002 ◽  
Vol 20 (7) ◽  
pp. 957-965 ◽  
Author(s):  
R. H. A. Iles ◽  
A. N. Fazakerley ◽  
A. D. Johnstone ◽  
N. P. Meredith ◽  
P. Bühler
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Wind Speed ◽  
Interplanetary Magnetic Field ◽  
Relativistic Electron ◽  
Radiation Belt ◽  
Solar Wind Speed ◽  
Recovery Phase ◽  
Magnetic Storms ◽  
Outer Radiation Belt

Abstract. The relativistic electron response in the outer radiation belt during magnetic storms has been studied in relation to solar wind and geomagnetic parameters during the first six months of 1995, a period in which there were a number of recurrent fast solar wind streams. The relativistic electron population was measured by instruments on board the two microsatellites, STRV-1a and STRV-1b, which traversed the radiation belt four times per day from L ~ 1 out to L ~ 7 on highly elliptical, near-equatorial orbits. Variations in the E > 750 keV and E > 1 MeV electrons during the main phase and recovery phase of 17 magnetic storms have been compared with the solar wind speed, interplanetary magnetic field z-component, Bz , the solar wind dynamic pressure and Dst *. Three different types of electron responses are identified, with outcomes that strongly depend on the solar wind speed and interplanetary magnetic field orientation during the magnetic storm recovery phase. Observations also confirm that the L-shell, at which the peak enhancement in the electron count rate occurs has a dependence on Dst *.Key words. Magnetospheric physics (energetic particles, trapped; storms and substorms) – Space plasma physics (charged particle motion and accelerations)

A UNIFYING THEORY OF HIGH-LATITUDE GEOPHYSICAL PHENOMENA AND GEOMAGNETIC STORMS

1961 ◽  
Vol 39 (10) ◽  
pp. 1433-1464 ◽  
Author(s):  
W. I. Axford ◽  
C. O. Hines
Keyword(s):  
Solar Wind ◽  
Steady State ◽  
High Latitude ◽  
Geomagnetic Storms ◽  
High Latitudes ◽  
Full Understanding ◽  
Earth’S Magnetosphere ◽  
Trapped Particles ◽  
Outer Portion ◽  
Earth's Magnetosphere

This paper is concerned with the occurrence at high latitudes of a large number of geophysical phenomena, including geomagnetic agitation and bay disturbances, aurorae, and various irregular distributions of ionospheric electrons. It shows that these may all be related in a simple way to a single causal agency, namely, a certain convection system in the outer portion of the earth's magnetosphere. The source of this convection is taken to be a viscous-like interaction between the magnetosphere and an assumed solar wind, though other sources of an equivalent nature may also be available. The model is capable of accounting for many aspects of the phenomena concerned, including the morphology of auroral forms and the occurrence of 'spiral' patterns in the loci of maximum intensities of several features. It also bears directly on the steady state of the magnetosphere, and in particular on the production of trapped particles in the outer Van Allen belt. In short, it provides a new basis on which a full understanding of these several phenomena may in time be built.

scholarly journals Solar wind interaction with the Earth's magnetosphere: the role of reconnection in the presence of a large scale sheared flow

2009 ◽  
Vol 16 (1) ◽  
pp. 1-10 ◽  
Author(s):  
F. Califano ◽  
M. Faganello ◽  
F. Pegoraro ◽  
F. Valentini
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Reconnection ◽  
Large Scale ◽  
Initial Conditions ◽  
Magnetic Layer ◽  
Magnetic Islands ◽  
Solar Wind Interaction ◽  
Earth’S Magnetosphere ◽  
Earth's Magnetosphere

Abstract. The Earth's magnetosphere and solar wind environment is a laboratory of excellence for the study of the physics of collisionless magnetic reconnection. At low latitude magnetopause, magnetic reconnection develops as a secondary instability due to the stretching of magnetic field lines advected by large scale Kelvin-Helmholtz vortices. In particular, reconnection takes place in the sheared magnetic layer that forms between adjacent vortices during vortex pairing. The process generates magnetic islands with typical size of the order of the ion inertial length, much smaller than the MHD scale of the vortices and much larger than the electron inertial length. The process of reconnection and island formation sets up spontaneously, without any need for special boundary conditions or initial conditions, and independently of the initial in-plane magnetic field topology, whether homogeneous or sheared.

scholarly journals Interplanetary magnetic field rotations followed from L1 to the ground: the response of the Earth's magnetosphere as seen by multi-spacecraft and ground-based observations

2011 ◽  
Vol 29 (9) ◽  
pp. 1549-1569 ◽  
Author(s):  
M. Volwerk ◽  
J. Berchem ◽  
Y. V. Bogdanova ◽  
O. D. Constantinescu ◽  
M. W. Dunlop ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Dynamic Pressure ◽  
Earth’S Magnetosphere ◽  
Solar Wind Magnetic Field ◽  
Earth's Magnetosphere ◽  
High Dynamic ◽  
First Time ◽  
Current Systems ◽  
The Magnetic Field

Abstract. A study of the interaction of solar wind magnetic field rotations with the Earth's magnetosphere is performed. For this event there is, for the first time, a full coverage over the dayside magnetosphere with multiple (multi)spacecraft missions from dawn to dusk, combined with ground magnetometers, radar and an auroral camera, this gives a unique coverage of the response of the Earth's magnetosphere. After a long period of southward IMF Bz and high dynamic pressure of the solar wind, the Earth's magnetosphere is eroded and compressed and reacts quickly to the turning of the magnetic field. We use data from the solar wind monitors ACE and Wind and from magnetospheric missions Cluster, THEMIS, DoubleStar and Geotail to investigate the behaviour of the magnetic rotations as they move through the bow shock and magnetosheath. The response of the magnetosphere is investigated through ground magnetometers and auroral keograms. It is found that the solar wind magnetic field drapes over the magnetopause, while still co-moving with the plasma flow at the flanks. The magnetopause reacts quickly to IMF Bz changes, setting up field aligned currents, poleward moving aurorae and strong ionospheric convection. Timing of the structures between the solar wind, magnetosheath and the ground shows that the advection time of the structures, using the solar wind velocity, correlates well with the timing differences between the spacecraft. The reaction time of the magnetopause and the ionospheric current systems to changes in the magnetosheath Bz seem to be almost immediate, allowing for the advection of the structure measured by the spacecraft closest to the magnetopause.

scholarly journals Chasing Down the Slow Solar Wind

Eos ◽  
2016 ◽  
Vol 97 ◽  
Author(s):  
Larry Kepko
Keyword(s):  
Solar Wind ◽  
Slow Solar Wind ◽  
Earth’S Magnetosphere ◽  
Earth's Magnetosphere

The Sun's plasma blasts Earth's magnetosphere at more than a million miles per hour. The fastest pours from holes in the corona, but until recently the source of the "slow" solar wind was a mystery.

Sign in / Sign up

Export Citation Format

Share Document