E.Yu. Budnik

The cusp/magnetosheath interface on May 29, 1996: Interball‐1 and Polar observations

On May 29, 1996, under steady strong northward IMF and high solar wind dynamic pressure conditions both Polar and Interball cross field lines that pass through the northern cusp and apparently close to the post-cusp reconnection site. The magnetopause current observed by Interball consists of two quite distinct layers, an inner broad current that is quite turbulent and another current that is quite abrupt and quiet. Polar also crosses current layers, similar to the Interball inner one. These observations support a model in which cusp field lines experience essentially stochastic behavior but on average provide topological connection between the cusp and magnetosheath.

The ion differential spectra in outer boundary of the ring current: November 17, 1995 case study

Abstract The analysis of the ion spectra variations is presented for the particles in the energy range from 0.5 keV to 3 MeV during INTERBALL-Tail Probe crossing of the plasma sheet-ring current region on November 17, 1995. The CORALL, DOK-2 and SKA-2 instrument data were used for spectra restoring. It is shown ion spectra have the same smooth shape (with the averaging time ∼2 min ) by traversing the satellite from 20Re up to 6Re. In particular, the spectra shape was almost constant with decreasing of geocentric distance from Re=11 to 6. Possible reasons of spectra variations are discussed.

Dispersive magnetosheath‐like ion injections in the evening sector on January 11, 1997

While the plasma cloud of the January 1997 CME event was passing the Earth, the Interball Auroral Probe (Interball-2) crossed the duskside auroral oval toward a contracted polar cap. The PROMICS-3 plasma instrument observed several consecutive dispersion ramps of magnetosheath-like protons over a wide range of magnetic local times (16–21 MLT). The last dispersion ramps were observed at later local times than previously reported, likely caused by the extreme conditions during a period when the magnetosphere was immersed in the dense plasma cloud. The Polar/VIS images of the oval show a very contracted polar cap. During the first clear dispersion event energetic oxygen ions were detected. They were also observed by the the particle detectors of Polar which was in close conjugation with Interball-2 right at this moment. We suggest that the dispersion ramps are signatures of ion injections formed by impulsive entry of magnetosheath ions through the dusk-side flank into the magnetosphere during a period of strongly northward IMF and contracted polar cap.

INTERBALL/Tail observations of high latitude pressure distribution

Abstract The determination of the real high latitude ring current distribution can be made if radial and azimuthal plasma pressure gradients are known. At high latitudes the plasma pressure is nearly isotropic, its calculation requires measurements of particle fluxes in the energy range from 0.1 to the hundreds of keV. Plasma pressure along the trajectory of INTERBALl/Tail Probe was calculated using data of CORALL and DOK-2 devices. It is shown that in most cases plasma pressure increases with the decrease of geocentric distances. The case is selected when pronounced pressure plateau is observed.

Magnetospheric plasma pressure and space weather

Abstract The atmospheric pressure is the main parameter measured for ordinary weather prediction. Plasma pressure is the main parameter determining the equilibrium of the magnetosphere, structure of the transverse and field- aligned currents. Transverse currents determine the value of D st -variation. Field-aligned currents determine the large-scale ionospheric electric fields and plasma transport. So the obtaining of magnetospheric plasma pressure distribution can be one of the main step in the solution of space weather problem. INTERBALL/Tail observations are used for determination of plasma pressure distribution with rather high accuracy.

The main features of the ion spectra variations in the transition region from dipole to tailward streched field lines

Abstract The variations of the ion spectra in the transition region from dipole to tailward stretched field lines are analyzed on the base of INTERBALL/Tail satellite observations. The simultaneous measurements of the CORALL, DOK-2 and SKA-2 instruments were used for the obtaining the ion spectra in a wide energy range. The events of small spectra variations along the satellite trajectory are selected. Some possibilities to explain the observed feature are analysed including the satellite travelling along single field line, the compensation of the loses of particles due to drift effects by the adiabatic acceleration due to the regular earthward drift in the dawn-dusk electric field, and intense plasma mixing in the conditions of the nonconservation of the magnetic moments of particles. It is shown that the action of turbulent auroral electric fields is the most probable explanation of the observed effect.

The Structure of Ion Spectra in Outer Regions of the Ring Current: The November 13, 1995 Event

We present the results on variations of ion spectra in the energy range from 1 keV to 3 MeV. The spectra measured onboard the INTERBALL Tail Probe satellite on November 13, 1995, during the satellites passage from the dipole field lines to the lines stretched into the magnetotail are analyzed. The data of the CORALL, DOK-2, and SKA-2 instruments are used to reconstruct the ion spectra. It is shown that, when the ion spectrum along the satellite trajectory is averaged over 2-min intervals, it is smooth up to geocentric distances of 6RE. With decreasing distances, the form of the particle spectra in the region under consideration remained virtually unchanged (region from L = 11RE down to L= 6RE) and only insignificant variations of the energy of the spectral maxima are observed. Possible reasons for the observed regularities are discussed.