LABORATORY SIMULATION OF THE SOLAR WIND MAGNETOSPHERE INTERACTION

1963 ◽  
Vol 41 (11) ◽  
pp. 1747-1752 ◽  
Author(s):  
F. J. F. Osborne ◽  
I. P. Shkarofsky ◽  
J. V. Gore

A controlled plasma–magnetic field interaction has been achieved, the conditions of which are such as to fulfill generally the scaling considerations of some aspects of geophysical phenomena, in particular the initial commencement of a magnetic storm. The preliminary measurements indicate the sweeping action on a magnetic field by a moving plasma; the formation of a magnetic cavity; the motion of the "dip pole" under perturbed conditions; the stand-off of plasma; a quasi Van Allen belt whose drift westward can be suggested as a ring current mechanism; and a polar trapping region. The correlations between the laboratory observations, geophysical measurements, and related theories, where possible, show no serious discrepancies as yet.

2013 ◽  
Vol 20 (1) ◽  
pp. 19-23 ◽  
Author(s):  
V. M. Vasyliūnas

Abstract. The depression of the horizontal magnetic field at Earth's equator for the largest imaginable magnetic storm has been estimated (Vasyliūnas, 2011a) as −Dst ~ 2500 nT, from the assumption that the total pressure in the magnetosphere (plasma plus magnetic field perturbation) is limited, in order of magnitude, by the minimum pressure of Earth's dipole field at the location of each flux tube. The obvious related question is how long it would take the solar wind to supply the energy content of this largest storm. The maximum rate of energy input from the solar wind to the magnetosphere can be evaluated on the basis either of magnetotail stress balance or of polar cap potential saturation, giving an estimate of the time required to build up the largest storm, which (for solar-wind and magnetospheric parameter values typical of observed superstorms) is roughly between ~2 and ~6 h.


2004 ◽  
Vol 22 (8) ◽  
pp. 2989-2996 ◽  
Author(s):  
Y. P. Maltsev ◽  
A. A. Ostapenko

Abstract. Based on magnetic data, spatial distribution of the westward ring current flowing at |z|<3 RE has been found under five levels of Dst, five levels of the interplanetary magnetic field (IMF) z component, and five levels of the solar wind dynamic pressure Psw. The maximum of the current is located near midnight at distances 5 to 7 RE. The magnitude of the nightside and dayside parts of the westward current at distances from 4 to 9 RE can be approximated as Inight=1.75-0.041 Dst, Inoon=0.22-0.013 Dst, where the current is in MA. The relation of the nightside current to the solar wind parameters can be expressed as Inight=1.45-0.20 Bs IMF + 0.32 Psw, where BsIMF is the IMF southward component. The dayside ring current poorly correlates with the solar wind parameters.


2021 ◽  
Vol 44 ◽  
pp. 12-15
Author(s):  
I.V. Despirak ◽  
◽  
N.G. Kleimenova ◽  
A.A. Lubchich ◽  
P.V. Setsko ◽  
...  

For this analysis, we selected the supersubstorm (SSS) occurred during the strong magnetic storm on 28 May 2011 (SYM/H~100 nT). The ground-based magnetic effects of SSS have been studied basing on the data from the global SuperMAG, INTERMAGNET and IMAGE magnetometer networks, as well as on the magnetic measurements by the ionospheric satellite AMPERE system. According to the SML- index behavior, the SSS event maximum was identified at ~09:00 UT on 28 May 2011 (SML= ~-2600 nT). The SSS occurred during the passage of the magnetic cloud in the solar wind. Before the SSS, the BZ component of the Interplanetary Magnetic Field (IMF) was negative, the IMF BY component was positive, and the local jump in the solar wind dynamic pressure was registered. We found that the SSS developed in the magnetosphere in the global scale. A strong westward electrojet was observed at auroral latitudes from the evening side to the dayside. In contrast to the typical scenario of a classical substorm, a very intense eastward electrojet was detected in the afternoon-evening sector. That may be a result of the formation of an additional partial ring current during the supersubstorm.


Nature ◽  
1972 ◽  
Vol 236 (5347) ◽  
pp. 381-385 ◽  
Author(s):  
P. DYAL ◽  
C. W. PARKIN ◽  
C. W. SNYDER ◽  
D. R. CLAY

1958 ◽  
Vol 6 ◽  
pp. 295-311
Author(s):  
V. C. A. Ferraro

The evidence in favour of a corpuscular theory of magnetic storms is briefly reviewed and reasons given for believing that the stream must be neutral but ionized and carry no appreciable current. It is shown that under suitable conditions the stream is able to pass freely through a solar magnetic field; the stream may also be able to carry away with it a part of this field. However, because of geometrical broadening of the stream during its passage from the sun to the earth, the magnetic field imprisoned in the gas may be wellnigh unobservable near the earth.The nature, composition and dimensions of the stream near the earth are discussed and it is concluded that on arrival the stream will present very nearly a plane surface to the earth if undistorted by the magnetic field.Because of its large dimensions, the stream will behave as if it were perfectly conducting. During its advance in the earth's magnetic field the currents induced in the stream will therefore be practically confined to the surface. The action of the magnetic field on this current is to retard the surface of the stream which being highly distortible will become hollowed out. Since the stream surface is impervious to the interpenetration of the magnetic tubes of force, these will be compressed in the hollow space. The intensity of the magnetic field is thereby increased and this increase is identified with the beginning of the first phase of a magnetic storm. This increase will be sudden, as observed, owing to the rapid approach of the stream to the earth.The distortion of the stream surface is discussed and it is pointed out that two horns will develop on the surface, one north and the other south of the geomagnetic equator. Matter pouring through these two horns will find its way to the polar regions.The main phase of a magnetic storm seems most simply explained as due to a westward ring-current flowing round the earth in its equatorial plane. Under suitable conditions such a ring-current would be stable if once set up. The mode of formation of the ring is, however, largely conjectural. The possibility that the main phase may be of atmospheric origin is also briefly considered. It is shown that matter passing through the two horns to the polar regions could supply the energy necessary for the setting up of the field during the main phase. The magnetic evidence in favour of such a hypothesis, however, seems wanting.


2012 ◽  
Vol 117 (A9) ◽  
pp. n/a-n/a ◽  
Author(s):  
Margaret W. Chen ◽  
Colby L. Lemon ◽  
Timothy B. Guild ◽  
Michael Schulz ◽  
James L. Roeder ◽  
...  

2004 ◽  
Vol 31 (21) ◽  
pp. n/a-n/a ◽  
Author(s):  
C. Lemon ◽  
R. A. Wolf ◽  
T. W. Hill ◽  
S. Sazykin ◽  
R. W. Spiro ◽  
...  

2018 ◽  
Author(s):  
Liudmila I. Gromova ◽  
Matthias Förster ◽  
Iakov I. Feldstein ◽  
Patricia Ritter

Abstract. Hall current variations in different time sectors during six magnetic storms of the summer seasons in 2003 and 2005 are examined in detail: three storms in the day-night meridional sector and three storms in the dawn-dusk sector. We investigate the sequence of the phenomena, their structure, positions and the density of the polar (PE) and the auroral (AE) Hall electrojets using scalar magnetic field measurements obtained from the CHAMP satellite in accordance with the study of Ritter et al. (2004a). Particular attention is devoted to the spatial-temporal behaviour of the PE at ionospheric altitudes during daytime hours both under geomagnetically quiet and under magnetic storm conditions. We analyze the correlations of the PE and AE with various activity indices like SYM/H and ASYM/H, that stand for large-scale current systems in the magnetosphere, AL for ionospheric currents, and the IndN coupling function for the state of the solar wind. We obtain regression relations of the magnetic latitude MLat and the electrojet current density I with those indices and with the interplanetary By and Bz magnetic field components. For the geomagnetic storms during summer seasons investigated here, we obtain the following typical characteristics for the electrojets' dynamics: 1. The PE appears at magnetic latitudes (MLat) and local times (MLT) of the cusp position. 2. This occurs in the day-time sector at MLat ∼ 73°–80° with a westward or an eastward direction, depending on the orientation of the IMF By component. Changes of current flow direction in the PE can occur repeatedly during the storm, but only due to changes of the IMF By orientation. 3. The current density in the PE increases with the intensity of the IMF By component from I ∼ 0.4 A/m for By ∼ 0 nT up to I ∼ 1.0 A/m for By ∼ 23 nT. 4. The MLat position of the PE does not depend on the orientation and the strength of the IMF By component. It depends, however, on the strength of the IMF Bz component. 5. The PE is situated at MLat ∼ 73° on the dayside during geomagnetically quiet periods and the recovery phase of a magnetic storm, and it shifts equatorward during intense substorms and the main phase of a storm. 6. There is no connection between MLat and the current density I in the PE with the magnetospheric ring current DR (index SYM/H). 7. There is a correlation between the current density I in the PE and the partial ring current in the magnetosphere (PRC, index ASYM/H), but practically no correlation of this index with MLat of the PE. 8. Substorms that occur before and during the beginning of a storm main phase are accompanied in the daytime by the appearance of an eastward electrojet (EE) at MLat ∼ 64° and then also by a westward electrojet (WE). In the nighttime sector the WE appears at MLat ∼ 64°. 9. During the development of the main storm phase, the daytime EE and the nighttime WE shift toward subauroral latitudes of MLat ∼ 56° and intensify up to I ∼ 1.5 A/m. Both electrojets persist during the main phase of the storm. The WE is then located about 6° closer to the pole than the EE during evening hours and about 2°–3° during daytime hours.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Shrikanth Kanekal ◽  
Yoshizumi Miyoshi

AbstractThe Earth’s magnetosphere is region that is carved out by the solar wind as it flows past and interacts with the terrestrial magnetic field. The inner magnetosphere is the region that contains the plasmasphere, ring current, and the radiation belts all co-located within about 6.6 Re, nominally taken to be bounding this region. This region is highly dynamic and is home to a variety of plasma waves and particle populations ranging in energy from a few eV to relativistic and ultra-relativistic electrons and ions. The interplanetary magnetic field (IMF) embedded in the solar wind via the process of magnetic reconnection at the sub-solar point sets up plasma convection and creates the magnetotail. Magnetic reconnection also occurs in the tail and is responsible for explosive phenomena known as substorms. Substorms inject low-energy particles into the inner magnetosphere and help generate and sustain plasma waves. Transients in the solar wind such as coronal mass ejections (CMEs), co-rotating interaction regions (CIRs), and interplanetary shocks compress the magnetosphere resulting in geomagnetic storms, energization, and loss of energetic electrons in the outer radiation belt nad enhance the ring current, thereby driving the geomagnetic dynamics. The Specification and Prediction of the Coupled Inner-Magnetospheric Environment (SPeCIMEN) is one of the four elements of VarSITI (Variability of the Sun and Its Terrestrial Impact) program which seeks to quantitatively predict and specify the inner magnetospheric environment based on Sun/solar wind driving inputs. During the past 4 years, the SPeCIMEN project has brought together scientists and researchers from across the world and facilitated their efforts to achieve the project goal. This review provides an overview of some of the significant scientific advances in understanding the dynamical processes and their interconnectedness during the VarSITI era. Major space missions, with instrument suites providing in situ measurements, ground-based programs, progress in theory, and modeling are briefly discussed. Open outstanding questions and future directions of inner magnetospheric research are explored.


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