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  • 1
    Electronic Resource
    Electronic Resource
    INTERBALL-Auroral observations of 0.1–12 keV ion gaps in the diffuse auroral zone (1999)
    Springer
    Annales geophysicae 17 (1999), S. 734-742 
    Details
    ISSN: 0992-7689
    Keywords: Magnetospheric physics (auroral phenomena; plasma convection)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract We examine ion flux dropouts detected by INTERBALL-Auroral upon traversal of the auroral zone at altitudes of ≈13 000 up to 20 000 km. These dropouts which we refer to as “gaps”, are frequently observed irrespectively of longitudinal sector and appear characteristic of INTERBALL-Auroral ion spectrograms. Whereas some of these gaps display a nearly monoenergetic character (≈12 keV), others occur at energies of a few hundreds of eV up to several keV. INTERBALL-Auroral data exhibit the former monoenergetic gap variety essentially in the evening sector. As examined in previous studies, these gaps appear related to transition from particle orbits that are connected with the magnetotail plasma source to closed orbits encircling the Earth. The latter gap variety, which spreads over several hundreds of eV to a few keV is often observed in the dayside magnetosphere. It is argued that such gaps are due to magnetospheric residence times well above the ion lifetime. This interpretation is supported by numerical orbit calculations which reveal extremely large (up to several tens of hours) times of flight in a limited energy range as a result of conflicting E × B and gradient-curvature drifts. The characteristic energies obtained numerically depend upon both longitude and latitude and are quite consistent with those measured in-situ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-999-0734-9
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  • 2
    Electronic Resource
    Electronic Resource
    Experimental study of the formation of inverted-V structures and their stratification using AUREOL-3 observations (2000)
    Springer
    Annales geophysicae 18 (2000), S. 1399-1411 
    Details
    ISSN: 0992-7689
    Keywords: Magnetospheric physics (current systems; energetic particles, precipitating; magnetosphere-ionosphere interactions)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract Multiple inverted-V structures are commonly observed on the same auroral zone crossing by a lowaltitude orbiting satellite. Such structures appear grouped and apparently result from an ionospheric and/or magnetospheric mechanism of stratification. More than two years of AUREOL-3 satellite observations were analyzed to study their properties and their formation in the framework of the ionosphere-magnetosphere coupling model proposed by Tverskoy. This model predicts some natural periodicity in the electrostatic potential profile (and subsequently in the field-aligned current profiles) that could account for oscillations experimentally observed in the auroral zone, such as successive inverted-Vs. Experimental results obtained during quiet or moderately active periods demonstrate that the number of structures observed within a given event is well described by a ‘scaling’ parameter provided by the hot plasma stratification theory and expressed in terms of the field-aligned current density, the total width of the current band, the plasma sheet ion temperature, and the height-integrated Pedersen conductivity of the ionosphere. The latitudinal width, in the order of 100/200 km at ionospheric altitudes, is relatively independent of the current density, and is determined not only by the existence of a potential difference above the inverted-Vs, but also by basic oscillations of the ionosphere-magnetosphere coupling system predicted by Tverskoy. The large number of cases studied by the AUREOL-3 satellite provides reliable statistical trends which permits the validation of the model and the inference that the multiple structures currently observed can be related directly to oscillations of the magnetospheric potential (or the pressure gradients) on a scale of ∼1000/2000 km in the near-Earth plasma sheet. These oscillations arise in the Tverskoy model and may naturally result when the initial pressure gradients needed to generate a large-scale field-aligned current have a sufficiently wide equatorial scale, of about 1 RE or more.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-000-1399-6
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  • 3
    Electronic Resource
    Electronic Resource
    The ion experiment onboard the Interball-Aurora satellite; initial results on velocity-dispersed structures in the cleft and inside the auroral oval (1998)
    Springer
    Annales geophysicae 16 (1998), S. 1056-1069 
    Details
    ISSN: 0992-7689
    Keywords: Magnetospheric physics ; Auroral phenomena ; Energetic particles Magnetopause cusp, and boundary layers ; Interball-Aurora satellite
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The Toulouse ION experiment flown on the Russian Interball-Aurora mission performs simultaneous ion and electron measurements. Two mass spectrometers looking in opposing directions perpendicular to the satellite spin axis, which points toward the sun, measure ions in the mass and energy ranges 1–32 amu and ∼0-14 000 eV. Two electron spectrometers also looking in opposing directions perform measurements in the energy range ∼10 eV-20 000 eV. The Interball-Aurora spacecraft was launched on 29 August 1996 into a 62.8° inclination orbit with an apogee of ∼3 RE. The satellite orbital period is 6 h, so that every four orbits the satellite sweeps about the same region of the auroral zone; the orbit plane drifts around the pole in ∼9 months. We present a description of the ION experiment and discuss initial measurements performed in the cusp near noon, in the polar cleft at dusk, and inside the proton aurora at dawn. Ion-dispersed energy structures resulting from time-of-flight effects are observed both in the polar cleft at ∼16 hours MLT and in the dawnside proton aurora close to 06 hours MLT. Magnetosheath plasma injections in the polar cleft, which appear as overlapping energy bands in particle energy-time spectrograms, are traced backwards in time using a particle trajectory model using 3D electric and magnetic field models. We found that the cleft ion source is located at distances of the order of 18 RE from the earth at about 19 MLT, i.e., on the flank of the magnetopause. These observations are in agreement with flux transfer events (FTE) occurring not only on the front part of the magnetopause but also in a region extending at least to dusk. We also show that, during quiet magnetic conditions, time-of-flight ion dispersions can also be measured inside the dawn proton aurora. A method similar to that used for the cleft is applied to these auroral energy dispersion signatures. Unexpectedly, the ion source is found to be at distances of the order of 60–80 RE, at the dawn flank of the magnetosphere. These results are discussed in terms of possible entry, acceleration, and precipitation mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-998-1056-z
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  • 4
    Electronic Resource
    Electronic Resource
    Stationary magnetospheric convection on November 24, 1981. 2.Small-scale structures in the dayside cusp/cleft (1999)
    Springer
    Annales geophysicae 17 (1999), S. 375-388 
    Details
    ISSN: 0992-7689
    Keywords: Magnetospheric physics (current systems; magnetopause cusp, and boundary layers; solar wind-magnetosphere interactions)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract A case study of the dayside cusp/cleft region during an interval of stationary magnetospheric convection (SMC) on November, 24, 1981 is presented, based on detailed measurements made by the AUREOL-3 satellite. Layered small-scale field-aligned current sheets, or loops, superimposed to a narrow V-shaped ion dispersion structure, were observed just equatorward from the region of the “cusp proper”. The equatorward sheet was accompanied by a very intense and short (less than 1 s) ion intensity spike at 100 eV. No major differences were noted of the characteristics of the LLBL, or “boundary cusp”, and plasma mantle precipitation during this SMC period from those typical of the cusp/cleft region for similar IMF conditions. Simultaneous NOAA-6 and NOAA-7 measurements described in Despirak et al. were used to estimate the average extent of the “cusp proper” (defined by dispersed precipitating ions with the energy flux exceeding 10−3 erg cm−2 s−1) during the SMC period, as ≈0.73∼ ILAT width, 2.6–3.4 h in MLT, and thus the recently merged magnetic flux, 0.54–0.70 × 107 Wb. This, together with the average drift velocity across the cusp at the convection throat, ≈0.5 km s−1, allowed to evaluate the cusp merging contribution to the total cross-polar cap potential difference, ≈33.8–43.8 kV. It amounts to a quite significant part of the total cross-polar cap potential difference evaluated from other data. A “shutter” scenario is suggested for the ion beam injection/penetration through the stagnant plasma region in the outer cusp to explain the pulsating nature of the particle injections in the low- and medium-altitude cusp region.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s00585-999-0375-z
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  • 5
    Electronic Resource
    Electronic Resource
    Semen Samo $$\overset{\lower0.5em\hbox{$\smash{\scriptscriptstyle\smile}$}}{l} $$ lovich Moiseev (In honor of his 70th birthday) (2000)
    Springer
    Plasma physics reports 26 (2000), S. 372-373 
    Details
    ISSN: 1562-6938
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1134/1.952866
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