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An experimental and modeling study of soot formation during the shock-tube pyrolysis and oxidation of a number of aromatic and aliphatic hydrocarbons was performed. Hydrocarbons with different chemical structures, both aliphatic (methane, propane, and propylene) and aromatic (benzene, toluene, and ethylbenzene), were tested. The experiments showed that the soot formation during the pyrolysis, even in the presence of small amounts of oxygen, is accompanied by a temperature decrease. A new, essentially modified detailed kinetic model of soot formation is proposed, which was successfully tested by describing the published data on the temporal behavior of a number of key species during the initial stages of pyrolysis and oxidation of a number of hydrocarbons under various conditions. When applied to modeling our experimental data, it closely reproduced the time profiles of the soot yield and temperature for the shock-tube pyrolysis of methane, propane, and propylene, as well as benzene, toluene, and ethylbenzene, two sets of compounds of drastically different natures.

We present and discuss observations of a region in the high-latitude near-Earth outer magnetosphere when over a distance of 9 R E – from GSM [0.83 R E , 1.6 R E , 8.5 R E ] to [−0.957 R E , 10.175 R E , 12.738 R E ] – Interball-1 observed multiple alternative changes in plasma characteristics: hot plasma sheet population is replaced by a region of mixed magnetosheath – plasma sheet population with the presence of ionospheric ions and vice versa. In the ‘mixed’ region, both ion populations were nearly stagnant, their velocity rarely exceeded 50 km/s and plasma-sheet electrons were absent. Most of the time interplanetary magnetic field (IMF) clock angle was less than 90°, rotating to more than 270° at the end of the interval, IMF B x being positive and dominating. A flux transfer event was registered near the magnetopause. Plasma characteristics suggest that observations took place at the high-latitude boundary of the near-Earth plasma sheet on closed field lines. We suggest that the mixed regions are formed on filed lines first reconnected to the magnetosheath magnetic field, then draped and convected duskward and tailward and secondary reconnected and closed.

Exploration of plasma–plasma interactions at the high-latitude magnetopause versus a simulated sheared current sheet with strong fluctuations of realistic spectral shape, revealed a new type of dynamic equilibrium, in which nonlinear disturbances serve as an effective obstacle for 80% of the incident magnetosheath ions, providing also the exchange by ∼10% of plasma particles with the stagnant high-beta boundary layer in the minimum field region over the polar cusps. The measured waves, reflected upstream by the boundary, interact in the 3-wave manner with the magnetosonic (MS) fluctuations of the incident flow, resulting in their amplification and then decay into accelerated MS-jets and Alfven waves, driving decelerated flows at the Alfven speed. This impulsive momentum loss via the MS-jets contributes in the average flow bend around the magnetosphere. The leading jet appearance is suggested to be phase-synchronized with both the initial MS fluctuations and nonlinear cascades upstream at the magnetopause, which constitutes the wavy obstacle with multiple decays into the smaller MS-jets and Alfvenic flows. High dynamic pressure in the MS-jets does not fit their acceleration by a reconnection; instead the jets are able to initiate the driven reconnection in the process of interaction with a downstream magnetopause. The acceleration of the MS-jets is consistent with a Fermi-type mechanism, in which electric wave-trains play the role of a moving non-continuous ‘wall’. Estimations of the jet scales from the approach of a nonlinear Cherenkov resonance conforms 2–3 reflections of the jet from the ‘wall’ before overcoming the ‘wall’ potential barrier. We demonstrate quantitative agreement of the acceleration of the leading MS-jet in the process of inertial ion drift in variable electric fields. Current sheets, generated due to opposite sign of the ion and electron inertial drift, can account for the intermittency of the TBL fluctuations.

We study the characteristics of the ion population encountered in the high latitude magnetosphere in the vicinity of the terminator for two passes of the INTERBALL-1 satellite. Analysis of data from the Low Energy Plasma Composition Experiment (AMEI-2) reveals the coexisting of ions with different origin: 1) from composition point of view - Solar wind and ionospheric plasmas; 2) from spectral poi of view - plasma sheet-like ions with energy-per-charge above 4 keV/q, together with magnetosheath-like plasma in the mantle part of the region and accelerated up to ∼ 2 keV/q and heated isotropic Solar wind plasma. A remarkable phenomenon is the accelerated to equal energy-per-charge (2.35 – 4.64 keV/q) both SW and ionospheric ions observed on mantle field lines.

Multi-spacecraft tracing of the high latitude magnetopause (MP) and boundary layers and Interball-1 statistics indicate that: 1. (a) The turbulent boundary layer (TBL) is a persistent feature in the region of the cusp and ‘sash’, a noticeable part of the disturbances weakly depends on the interplanetary magnetic field By component; TBL is a major site for magnetosheath (MSH) plasma penetration inside the magnetosphere through percolation and local reconnection. 2. (b) The TBL disturbances are mainly inherent with the characteristic kinked double-slope spectra and, most probably, 3-wave cascading. The bi-spectral phase coupling indicates self-organization of the TBL as the entire region with features of the non-equilibrium multi-scale and multi-phase system in the near-critical state. 3. (c) We've found the different outer cusp topologies in summer/winter periods: the summer cusp throat is open for the decelerated MSH flows, the winter one is closed by the distant MP with a large-scale (∼several Re) diamagnetic ‘plasma ball’ inside the MP; the ‘ball’ is filled from MSH through patchy merging rather than large-scale reconnection. 4. (d) A mechanism for the energy release and mass inflow is the local TBL reconnection, which operates at the larger scales for the average anti-parallel fields and at the smaller scales for the nonlinear fluctuating fields; the latter is operative throughout the TBL. The remote from TBL anti-parallel reconnection seems to happen independently.

Presented are two cases when AMEI-2 instrument aboard INTERBALL-1 measures simultaneously He ++ and O + ions in near Earth magnetospheric boundary regions, connected to the cusp/cleft region. Data show that ionospheric ions could be accelerated to several keV by different mechanisms.

We present Interball Tail Probe observations from the high latitude mid-tail magnetopause which provide evidence of reconnection between the interplanetary magnetic field (IMF) and lobe field lines during a 6 h interval of stable northward and dawnward IMF on October 19, 1995. Results from a global magnetohydrodynamic simulation for this interval compare well with the Interball observations. With the simulations, we provide an extended global view of this event which gives us insight into the reconnection and convection dynamics of the magnetosphere. We find that reconnection occurs in a region of limited spatial extent near the terminator and where the IMF and the lobe field are anti-parallel. Reconnected IMF field lines drape over the dayside magnetosphere, convect along the flanks into the nightside, and enter the magnetotail through a small entry window that is located in the flank opposite to the reconnection site. Ionospheric convection is consistent with previous observations under similar IMF conditions and exhibits a two cell pattern with a dominant lobe cell over the pole. The magnetic mapping between the ionosphere and the lobe boundary is characterized by two singularities: the narrow entry window in the tail maps to a 6 h wide section of the ionospheric lobe cell. A singular mapping line cuts the lobe cell open and maps to almost the entire tail magnetopause. By this singularity the magnetosphere avoids having a stagnation point, i.e., the lobe cell center maps to a tailward convecting field line. The existence of singularities in the magnetic mapping between the ionosphere and the tail has important implications for the study of tail–ionosphere coupling via empirical magnetic field models. Because the lobe–IMF reconnection cuts away old lobe flux and replaces it with flux tubes of magnetosheath origin, solar wind plasma enters the lobes in a process that is similar to the one that operates during southward IMF.

The high-apogee Interball Tail Probe crosses the magnetopause in two latitude ranges: one is close to the equator, and the other is at middle and high latitudes. A brief description of dayside magnetopause observations from the fast plasma analyzer SCA-1 is given. We give examples of plasma regimes observed at low latitudes that show evidence for plasma cloud penetration into the magnetosphere. Nonstationary reconnection is suggested as a possible mechanism for the observed near-magnetopause structures.

The fast ion spectrometer SCA-1 on Interball Tail Probe measures 3-D ion distribution in the energy range 0.05–5.0 keV/Q in less than 10 sec. With new data we are testing the hypothesis, proposed on the basis of measurements on Prognoz-8 and Prognoz-10, that the thermalization of ion core on the strong Q-perpendicular shock front is provided by non-stationarity of the shock front. One supercritical Q-perpendicular bow shock crossing is analyzed. The downstream transmitted beam consists of multiple beams with thermal width of about upstream solar wind thermal width. This supports previous suggestion that the heated core of the downstream ion velocity distribution is formed of beamlets originating at patchy and oscillating structure of the shock front.

Analysis of several low Mach number interplanetary shocks have shown that the steepness of the amplitude spectrum of electric field fluctuations in the frequency range from several Hz to about 20 Hz is different at quasi-parallel shock front compared to the front of quasi-perpendicular shock. The amplitude of electric field fluctuations in the ion sound frequency range is also varying with the angle between the shock normal and magnetic field direction, Θ Bn . We extend our analysis to sample of bow shock crossings using the data of Prognoz-8 in order to verify the Θ Bn dependence of ELF noise for supercritical shocks.

Thestructureof the iondistributionfunctiondownstreamof thebowshockfrontisanalyzedwith theuseof ionenergyspectrameasuredwithhightemporalresolution(0.64sec) by severaldifferentlyorientednarrow—angleelectrostatic analyzersonboardPrognoz-1OIntercosmossatellite.Withina relativelyextendedregiondownstreamof the shockthe ionenergyspectraexhibitfinestructureconsistingof severalrapidlyvaryingnarrow peaks. Someevidenceexiststhatthe iondistributionfunctionbehinda strongquasiperpendicular shockconsistsof manynarrowbunches. Theelectrostaticpotentialjumpat thefrontof an obliqueshockmayoccurin a distanceof about2 km. Observations of the iondistributionfunctionis an importanttestand information source forthetheoreticaldescriptionof thecollisionlessshock. Observationsof doublepeakedionflowat theshockfront/1/provedtheimportanceof thereflectedbeamin the shockprocesses.Subsequentobservationson ISEE—1and—2 /2,3,4/and Prognoz-8/5/as wellas theoreticaldevelopments(e.g.,/6/)showeda moredetailedpictureof the reflectedbeamdynamicsand theroleof reflectedinnsin thedissipativeprocessesnear theshockfront. Itwasone of the importanttopicsof the INTERSHOCKproject/7/to provideadditionaldataon thestructureof theiondistribution function. Itwasexpectedthatthehighertemporalresolutionwouldhelpthedevelopmentof the incompletely solvedproblemof thedissipationin theshock.

An instrument for energy- and mass-spectrum measurements of ion fluxes in the Earth magnetotail is described. The ion selection by energy and mass is provided by sequential analysis of the incident ion beam in the electrostatic field of a cylindrical detector and the field of a permanent magnet. The measurement of ion energy distribution is carried out through scanning the voltage supplied to the electrostatic deflector. At a fixed energy the intensities of the different ion fluxes are measured simultaneously. An electrostatic angular scanner allows for the variation of the direction of the polar view-angle (in a frame of reference with a polar axis coincident with the spin axis of the spacecraft). The scanning of the azimuth angle is obtained while the satellite is spinning. The operational principle and the design of the instrument are described and the results from the laboratory testing are presented.

Observations of multiple crossings of the Earth's bow shock allow us to estimate the nature and velocity of bow shock motion. We have studied this motion with Prognoz 7, 8, 10, ISEE 1, 2 and IMP observations in two ways: by the time delay of bow shock crossings with two well separated satellites and by the difference in time between the bow shock crossings observed by one spacecraft and jumps in solar wind dynamic pressure observed by the other one. The qualitative interpretation of these data as a “surface wave” moving along the bow shock front allows us to estimate its velocity to be about several tens up to several hundreds km/s with mean value ∼100 km/s.

An original instrument for ion energy distribution measurement in ionospheric plasma above the F-layer was designed and launched on board the ‘INTERCOSMOS-BULGARIA-1300’ satellite. The instrument performs differential energy analysis of ion species within the two energy ranges of 1 – 27 eV/q and 0.2–8keV/q.

There is evidence of a strong influence of an atmospheric (cometary) interaction on the Martian tail formation: small total magnetic flux in the tail, the existence of plasma flow of apparently planetary origin, interplanetary magnetic field control of magnetic field orientation in the tail and other evidence. At the same time the large radius of the Martian magnetotail (about 2 planetary radii) can be considered as a strong evidence for the existence of a planetary magnetic field. Plasma and magnetic field properties in the Martian tail are in many respects similar to the ones observed in the tail of Venus. The limited amount of near-Mars measurements leads to some reservations in coming to definite conclusions. A combined magnetosphere of Mars is suggested that consists of two polar-tied magnetic tubes connected to the tail and an equatorial Venus-type interaction region in-between.

The results presented were obtained from experiments with temporal resolution of 0.02 to 1.28 sec that were carried out on board Prognoz 8 and 10 satellites. The following parameters and their changes after bow shock crossing have been taken into account: three dimensional drift velocity of total ion flow and ion temperature, and their fluctuations. The bow shock crossings under study involve both quasiparallel and quasiperpendicular strong shocks. In this paper, slow quasiperiodic fluctuations (10−4 + 10 Hz) in the downstream region are studied and the relation between these fluctuations and energy distribution function variations is discussed. Data from 13 selected shock wave crossings were used to investigate how the frequency of the oscillations depends on parameters characteristic for particular crossings.