Andre Balogh
Imperial College London, Pysics, Emeritus
ABSTRACT
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Nine coronal mass ejections (CMEs) have been detected in the solar wind by the Ulysses plasma experiment between 31° and 61° South. One of these events, which was also a magnetic cloud, was directly associated with an event observed by... more
Nine coronal mass ejections (CMEs) have been detected in the solar wind by the Ulysses plasma experiment between 31° and 61° South. One of these events, which was also a magnetic cloud, was directly associated with an event observed by the soft X-ray telescope on Yohkoh in which large magnetic loops formed in the solar corona directly beneath Ulysses. This association suggests that the flux rope topology of the magnetic cloud resulted from reconnection between the ``legs'' of neighboring magnetic loops within the rising CME. The average CME speed (˜740 km s-1) at these latitudes was comparable to that of the normal solar wind there and is much greater than average CME speeds observed either in the solar wind in the ecliptic plane or in the corona close to the Sun. We suggest that the same basic acceleration process applies to both slow CMEs and the normal solar wind at any latitude.
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Page 1. 1 DISAPPEARANCE OF THE HELIOSPHERIC SECTOR STRUCITJRE AT ULYSSES EJ Smithl, M. Neugebauerl, A. Balogh2, SJ Barnes, G. Erdos2, RJ Forsyth2, BE Goldstein, JL Phillipss, and BT Tsurutanil 1. Jet Propulsion Laboratory, California... more
Page 1. 1 DISAPPEARANCE OF THE HELIOSPHERIC SECTOR STRUCITJRE AT ULYSSES EJ Smithl, M. Neugebauerl, A. Balogh2, SJ Barnes, G. Erdos2, RJ Forsyth2, BE Goldstein, JL Phillipss, and BT Tsurutanil 1. Jet Propulsion Laboratory, California Institute of Technology ...
An investigation is presented on the properties of a well-defined energetic particle population in interplanetary space: protons in the energy range 30 to 1600 keV. Among the aspects of the study considered are: (1) the nature of the Low... more
An investigation is presented on the properties of a well-defined energetic particle population in interplanetary space: protons in the energy range 30 to 1600 keV. Among the aspects of the study considered are: (1) the nature of the Low Energy Proton experiment aboard the ISEE-3 satellite; (2) the traces of the magnetic field connection paths at the ISEE-3 position in question; (3) the beam-like flow of particles along the magnetic field during an upstream burst event from the direction of the earth; (4) the intensity increase of low-energy proton fluxes caused by the passage of the interplanetary shock wave; (5) the sudden proton flux decrease when energized proton-impenetrable, sudden magnetic field changes were swept past the satellite; and (6) the energy spectrum of solar wind and energetic protons, showing continuity between the two populations over many orders of magnitude in intensity and energy: implying a solar wind source of particles energized in interplanetary space.
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We report unambiguous evidence for rolled-up Kelvin-Helmholtz (KH) vortices that form in the nonlinear stage of the Kelvin-Helmholtz instability (KHI), based on multi-spacecraft measurements by Cluster at the dusk flank magnetopause... more
We report unambiguous evidence for rolled-up Kelvin-Helmholtz (KH) vortices that form in the nonlinear stage of the Kelvin-Helmholtz instability (KHI), based on multi-spacecraft measurements by Cluster at the dusk flank magnetopause during northward interplanetary magnetic field (IMF) periods. With the help of a three-dimensional MHD simulation of the KHI, signatures expected in the KH vortices at the magnetopause, namely, the magnetosheath plasma intruding into the magnetosphere, vortical plasma flow, and magnetic field perturbation pattern associated with the vortices, have been identified. In addition, plasmas of solar wind origin are present in the vicinity of the rolled-up vortices and on the magnetospheric side of the magnetopause. It is getting increasingly clear from theoretical studies that transport of plasma is inevitable in the rolled-up KH vortices. Thus our observations are precisely consistent with the scenario that, under northward IMF conditions, the KHI leads to th...
According to the observation data by the Cluster spacecraft encountering the mid-altitude cusp region and the theory research work of the formation mechanism of kinetic Alfven waves it can be concluded that kinetic Alfven waves can be... more
According to the observation data by the Cluster spacecraft encountering the mid-altitude cusp region and the theory research work of the formation mechanism of kinetic Alfven waves it can be concluded that kinetic Alfven waves can be come into being in the mid-altitude polar cusp Using the observation data detected by the Cluster CIS FGM and PEACE crossing through the mid-altitude cusp region on 4 July 2001 we find that ion and electron number densities are obviously disturbed and protons are always in the down-going direction We obtain that the values of plasma beta are in the range between 0 002 and 0 01 from 13 24 00 to 13 39 00 They are larger than the mass ratio value of electron and proton That implies the mid-altitude polar cusp is a kinetic region Ion and electron density inhomogeneity and the ion beam with down-going direction are the main factors for the formation of kinetic Alfven waves The observational results are consonant with the results obtained from the theory res...
The three-dimensional configuration of the four Cluster satellites can be used, in conjunction with ground observations, to analyze both the propagation and the coherence scale of ULF waves in the outer magnetosphere. We report here on... more
The three-dimensional configuration of the four Cluster satellites can be used, in conjunction with ground observations, to analyze both the propagation and the coherence scale of ULF waves in the outer magnetosphere. We report here on the results of analysis of several events in late 2001 in the Pc 3-4 band (15-100 mHz), both on closed dayside field lines and in the polar cap. We have found poor correlations between transverse wave components at the 4 Cluster spacecraft when they were in the dayside middle magnetosphere, with separation distances of ~1000 - 5000 km. Correlation was considerably better for the field-aligned component, suggesting that compressional waves correlated well but that the transverse wave scale (e.g., of local field line resonances) was quite short. In contrast, all components correlated much better for the same range of separation distances when the satellites were in the polar cap. We interpret this as showing the lack of local resonances, and thus the do...
The dynamics, shape and structure of the magnetopause can be unambiguously determined using the four spacecraft data from Cluster. Multi-spacecraft techniques can be applied which measure, for example: the extent of the current layer;... more
The dynamics, shape and structure of the magnetopause can be unambiguously determined using the four spacecraft data from Cluster. Multi-spacecraft techniques can be applied which measure, for example: the extent of the current layer; boundary orientation, thickness and motion, and local deviation from planarity. We investigate a number of magnetopause crossings observed by Cluster in these terms and also explore issues of identification, such as boundary crossing times. The analysis shows that, although often planar on presently covered Cluster spatial scales (100-3000 km), strong acceleration of the boundary is usually present and can affect the determination of boundary thickness at each spacecraft. The detailed nature of the magnetopause current layer, and of transient magnetic signatures such as FTEs, is also often directly calculated. The local direction of the magnetopause current, for example, consistantly compares well to observed plasma density and flows. Good knowledge of...
The Rosetta Plasma Consortium (RPC) is a 5 sensor experiment which is being carried on board by the Rosetta mission to study the plasma environment of the comet Wirtanen in 2012. At the centre of the five sensors is the Plasma Interface... more
The Rosetta Plasma Consortium (RPC) is a 5 sensor experiment which is being carried on board by the Rosetta mission to study the plasma environment of the comet Wirtanen in 2012. At the centre of the five sensors is the Plasma Interface Unit (PIU) which provides the common central processing and power condition for the five instruments as well as the only interface to the spacecraft subsystem. However the PIU have supplied more than hardware to the consortium - it has also been responsible for the organisational centre for the design, integration and testing of the RPC package and in future will be the centre focus for its operations. We describe how the main elements of the PIU fulfill the diverse functional and operational requirements of the sensors on the one hand, and the spacecraft interface on the other hand. Such packages, supporting diverse, multi-sensor scientific instruments are considered necessary for many future space missions. We will conclude with a brief discussion ...
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The association between the CLUSTER spacecraft and ground-based radars offers a unique opportunity to observe the signatures of transient reconnection simultaneously in the vicinity of the dayside magnetopause and at low altitude in the... more
The association between the CLUSTER spacecraft and ground-based radars offers a unique opportunity to observe the signatures of transient reconnection simultaneously in the vicinity of the dayside magnetopause and at low altitude in the ionosphere. We report here on such observations on March 17, 2001, during a short period when the IMF turns southward. Flow channels are observed in the vicinity of the ionospheric cusp by the SuperDARN HF radars. In the high altitude cusp, field and particle ob- servations from the various instruments onboard CLUSTER display the characteristic signatures of flux transfer events (FTEs) associated with reconnection at the mag- netopause. The two sets of data show a clear correlation. We discuss in detail these signatures, their compatibility and the implication on the structure and dynamics of the reconnected flux tube.
Understanding the interconnection between various regions in the solar-terrestrial en- vironment is one of the goals of space weather studies. Cluster, which is a great mis- sion from purely scientific aspects, also contributes to space... more
Understanding the interconnection between various regions in the solar-terrestrial en- vironment is one of the goals of space weather studies. Cluster, which is a great mis- sion from purely scientific aspects, also contributes to space weather through the in- creasing understanding of solar wind-magnetosphere coupling and certain magneto- spheric processes. Continuous observations by the four spacecraft, for the first time, enabled to deduce the temporal and spatial scales of the various disturbances in various regions in the disturbed magnetosphere both in global and local scales, especially if supported by other ISTP spacecraft. In this paper, representative events studied using Cluster observations during enhanced Sun-Earth coupling will be reviewed.
Plasma sheet bursty bulk flows (BBF) and the associated magnetic field fluctuations appear to exhibit characteristic features which are typical for hydrodynamic or MHD turbulence. Second order statistical description of turbulence... more
Plasma sheet bursty bulk flows (BBF) and the associated magnetic field fluctuations appear to exhibit characteristic features which are typical for hydrodynamic or MHD turbulence. Second order statistical description of turbulence includes the estimation of power-law scaling indices from power spectra over a range of frequencies. Here we estimate scaling indices by a novel wavelet method using FGM burst mode (~67 Hz) magnetic field measurements from the Cluster spacecraft. We show that the scaling index changes almost continuously on small and large scales. This statistical non-stationarity feature is caused by the occurrence of BBFs. The spectral index for small-scale, BBF-associated magnetic turbulence, estimated near the current sheet is close to 5/3, indicative of the inertial range energy spectrum of three-dimensional turbulence. Away from the current sheet the small-scale spectral index increases. Independent of position, large-scale spectral indices approach 3 which is indica...
Magnetospheric periodic substorms and the onset are very important elements in magnetospheric physics. During the last decade significant progress has been made in understanding them. The multipoint measurements available from the... more
Magnetospheric periodic substorms and the onset are very important elements in magnetospheric physics. During the last decade significant progress has been made in understanding them. The multipoint measurements available from the satellite mission and ground-based stations enable spatiotemporal effects in data sets to be resolved. In this paper, by combining CANOPUS stations, IMAGE, geosynchronous satellite data with magnetotail satellites observations,
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We present the first Cluster spacecraft study of the intense (deltaB/B~0.5, deltaE/VAB~0.5) equatorial plane surface waves diverging from magnetic reconnection in the geomagnetic tail at ~17 Re. Using phase lag analysis with... more
We present the first Cluster spacecraft study of the intense (deltaB/B~0.5, deltaE/VAB~0.5) equatorial plane surface waves diverging from magnetic reconnection in the geomagnetic tail at ~17 Re. Using phase lag analysis with multi-spacecraft measurements, we quantitatively determine the wavelength and phase velocity of the waves with spacecraft frame frequencies from 0.03 Hz to 1 Hz and wavelengths from much larger (4Re) than to comparable to the H+ gyroradius (~300km). The phase velocities track the strong variations in the equatorial plane projection of the reconnection outflow velocity perpendicular to the magnetic field. The propagation direction and wavelength of the observed surface waves resemble those of flapping waves of the magnetotail current sheet, suggesting a same origin shared by both of these waves. The observed waves appear ubiquitous in the outflows near magnetotail reconnection. Evidence is found that the observed waves are associated with velocity shear in reconn...
We report on the dynamical variation of the current sheet structure in the magnetotail using magnetic field and plasma data obtained by the Cluster multi-satellites. It is found that in some cases the thickness of the cross-tail current... more
We report on the dynamical variation of the current sheet structure in the magnetotail using magnetic field and plasma data obtained by the Cluster multi-satellites. It is found that in some cases the thickness of the cross-tail current sheet shows temporal variations repeatedly. This sausage-mode-like variation is associated with substorm onsets or occurrence of fast plasma flows, with the time
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The tail current sheet and its dynamics are one of the most essential elements in magnetospheric physics. By analyzing Cluster magnetic field data we investigate the temporal and spatial structure of the current sheet between X = -15 and... more
The tail current sheet and its dynamics are one of the most essential elements in magnetospheric physics. By analyzing Cluster magnetic field data we investigate the temporal and spatial structure of the current sheet between X = -15 and -19 RE. From the observations in 2001, when the Cluster tetrahedron scale was 2000 km, it was shown that thin current
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During last six years two main destructive floods occurred in Calabria, the southern- most tip of italian peninsula. These events are known as Crotone (October 1996) and Soverato (September 2000) floods by the name of cities that received... more
During last six years two main destructive floods occurred in Calabria, the southern- most tip of italian peninsula. These events are known as Crotone (October 1996) and Soverato (September 2000) floods by the name of cities that received most destruc- tive effects and losses of live. Floods were very different: rainfall lasted for three days during the Soverato flood while
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We examined the structure of the tail current sheet at XGSM˜-19~R_E using fast flapping oscillation. It was found that during 1055 -1107 UT on 29 August 2001 and 2220 - 2235 UT on 26 September 2001, following substorm intensifications,... more
We examined the structure of the tail current sheet at XGSM˜-19~R_E using fast flapping oscillation. It was found that during 1055 -1107 UT on 29 August 2001 and 2220 - 2235 UT on 26 September 2001, following substorm intensifications, the flapping current sheet displayed a clearly bifurcated structure with current density peaks at |B_x|˜0.5~B_L and a pronounced broad current density
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Thin current sheets with a thickness of less than a few ion gyro radii are known to play an important role in the energy conversion process in the magnetotail. During summer 2003, when the tetrahedron scale of Cluster was about 250 km,... more
Thin current sheets with a thickness of less than a few ion gyro radii are known to play an important role in the energy conversion process in the magnetotail. During summer 2003, when the tetrahedron scale of Cluster was about 250 km, fine structures of thin current sheets were resolved using multipoint measurements. We examined the detailed structures of thin
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On board of the four Cluster satellites launched in summer 2000 two instruments are measuring the magnetic field magnitude: the flux-gate magnetometer (FGM) and the electron drift instrument (EDI). This gives the possibility of an... more
On board of the four Cluster satellites launched in summer 2000 two instruments are measuring the magnetic field magnitude: the flux-gate magnetometer (FGM) and the electron drift instrument (EDI). This gives the possibility of an ABSOLUTE measurement of the magnetic field vector and enhances the value of the multipoint measurements on Cluster. The errors of the respective measurements are discussed
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In February of 2001, the Cluster orbit plane lined up approximately along the noon-midnight meridian, affording passages through the northern and southern high-altitude cusps. During this period the FAST orbit provided passes through the... more
In February of 2001, the Cluster orbit plane lined up approximately along the noon-midnight meridian, affording passages through the northern and southern high-altitude cusps. During this period the FAST orbit provided passes through the southern low-altitude cusp and polar cap at much lower ( ~3000 km) altitudes. In the interval from 23:10 UT on 20 February through at least 00:30
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We study substorm energy storage and release process in the magnetotail by analyzing Cluster data during a multi-onset substorm on August 12, 2001. The Cluster space- craft, with their high-inclination orbit, observe enhanced convection... more
We study substorm energy storage and release process in the magnetotail by analyzing Cluster data during a multi-onset substorm on August 12, 2001. The Cluster space- craft, with their high-inclination orbit, observe enhanced convection and associated thinning of the plasma sheet before the major onset and dipolarization and associated flow events during the expansion phase simultaneously at different locations. Using
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The four Cluster spacecraft made observations near the dusk flank boundary layer during a north-to-south passage at a location near X=-5 Re on November 20-21, 2001. The IMF remained quite steady and northward while a decreasing solar wind... more
The four Cluster spacecraft made observations near the dusk flank boundary layer during a north-to-south passage at a location near X=-5 Re on November 20-21, 2001. The IMF remained quite steady and northward while a decreasing solar wind kinetic pressure moved the boundary outward and kept it near Cluster for almost 20 hours. Magnetic field and plasma measurements revealed repeated
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During geomagnetically active times, the ionospheric contribution to the plasma sheet can be significant. Because of the larger Larmor radius of the O+ ions, the motion of O+ is more likely than H+ to be non-adiabatic in the thin current... more
During geomagnetically active times, the ionospheric contribution to the plasma sheet can be significant. Because of the larger Larmor radius of the O+ ions, the motion of O+ is more likely than H+ to be non-adiabatic in the thin current sheets that are formed during substorms. The non-adiabatic ions then stream along the current sheet from dawn-to-dusk, in what are called "Speiser Orbits." It has been shown theoretically that there exist equilibrium models of thin plasma sheets where the cross-tail current is carried by the Speiser orbit particles, but this has never been tested experimentally. We have used CIS/CODIF from the CLUSTER satellites to first determine the contribution of H+ and O+ to the plasma sheet pressure during substorms, when the CLUSTER satellites are located close to the near-earth neutral line. We find that there are cases during storm-times when energetic O+ (~ 30 keV) is the dominant contributer to the plasma sheet pressure. Examination of the distr...
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The Venus Express mission is scheduled for launch in 2005. Among many other instruments, it carries a magnetometer to investigate the Venus plasma environment. Although Venus has no intrinsic magnetic moment, magnetic field measurements... more
The Venus Express mission is scheduled for launch in 2005. Among many other instruments, it carries a magnetometer to investigate the Venus plasma environment. Although Venus has no intrinsic magnetic moment, magnetic field measurements are ...
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... Marsden et al., 1990bR.G. Marsden, VV Afonin, A. Balazs, G. Erdös, JPG Henrion, AK Richter, P. Rusznyak, A. Somogyi, S. Szalai, A. Varga, L. Varhalmi, K.-P. Wenzel and M. Witte, The Phobos Low Energy Telescope charged particle... more
... Marsden et al., 1990bR.G. Marsden, VV Afonin, A. Balazs, G. Erdös, JPG Henrion, AK Richter, P. Rusznyak, A. Somogyi, S. Szalai, A. Varga, L. Varhalmi, K.-P. Wenzel and M. Witte, The Phobos Low Energy Telescope charged particle experiment, Nucl. Instrum. Meth. ...
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ABSTRACT
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... 207 209 TIME {TIC--1ZHR) 93 3UL 24 Figure 2. A CIR at -36 ø latitude and 4.5 AU from the Sun. The three boundaries within the CIR are indicated by vertical dashed lines. The region of interest, from the stream interface (IF) to the... more
... 207 209 TIME {TIC--1ZHR) 93 3UL 24 Figure 2. A CIR at -36 ø latitude and 4.5 AU from the Sun. The three boundaries within the CIR are indicated by vertical dashed lines. The region of interest, from the stream interface (IF) to the reverse shock (RS) is shaded. ...