Magnetic storm cessation during sustained northward IMF

Times of sustained strong northward IMF can interrupt the magnetic storm development and lead to lower levels of geomagnetic activity for many hours. During 1997–2000 we have found two events of this kind observed on November 8, 1998 and October 13, 2000. In both cases, the storms started as usual after arrival of ejecta with a southward IMF component from the Sun to the Earth, but ceased after several hours due to the onset of sustained northward IMF leading to the faster recovery process. After the passage of this so-called positive domain, the storm development started again. The heliospheric magnetic field intensity remained enhanced and nearly constant. The solar origins of the geomagnetic storm interruptions have been investigated. Tentatively they may be related to strong nonlinear Alfvйn type solitary waves excited by non-stationary coronal current variations with a characteristic time-scale of about a day.     

Providing the maximum cycle work as a promising direction in development of gas turbine plants

We consider a possibility of providing the equality of the maximum simple cycle work without energy losses caused by irreversibility of compression and expansion processes and the work of a complex cycle obtained from the simple cycle by introducing the intermediate heating under condition of the equality of effective efficiencies of the simple and complex cycles and an increase of the efficiency of the compression and expansion processes in prospect.     

Calculation and experimental investigation of mixture formation in a vortex mixer

The paper presents the investigation results for an ejection device of preliminary preparation of a fuel-air mixture for low emission combustion chambers. The process of mixture formation was simulated numerically. The experimental investigation of oxidant and gaseous fuel mixing was carried out and the characteristic dependences of the mixture concentration distribution in the exit section were obtained.     

Performance of the IRI-2007 model for equatorial topside ion density in the African sector for low and extremely low solar activity

The recent availability of new data sets during the recent extreme solar minimum provides an opportunity for testing the performance of the International Reference Ionosphere in historically undersampled regions. This study presents averages and variability of topside ionospheric densities over Africa as a function of season, local time, altitude, and magnetic dip latitude as measured by the Communication/Navigation Outage Forecast System (C/NOFS) satellite. The results are compared to the three topside model options available in IRI-2007. Overall, the NeQuick model is found to have the best performance, though during the deepest part of the solar minimum all three options significantly overestimate density.     

Analysis of 630.0-nm Emission Sources in Auroras

Cosmic Research - The role is considered of all known potential sources of excitation of the 1D term of atomic oxygen in auroras and the value of their relative contributions to the emission...     

Planetary protection program for Mars 94/96 mission.

Mars surface in-situ exploration started in 1975 with the American VIKING mission. Two probes landed on the northern hemisphere and provided, for the first time, detailed information on the martian terrain, atmosphere and meteorology. The current goal is to undertake larger surface investigations and many projects are being planned by the major Space Agencies with this objective. Among these projects, the Mars 94/96 mission will make a major contributor toward generating significant information about the martian surface on a large scale. Since the beginning of the Solar System exploration, planets where life could exist have been subject to planetary protection requirements. Those requirements accord with the COSPAR Policy and have two main goals: the protection of the planetary environment from influence or contamination by terrestrial microorganisms, the protection of life science, and particularly of life detection experiments searching extra-terrestrial life, and not life carried by probes and spacecrafts. As the conditions for life and survival for terrestrial microorganisms in the Mars environment became known, COSPAR recommendations were updated. This paper will describe the decontamination requirements which will be applied for the MARS 94/96 mission, the techniques and the procedures which are and will be used to realize and control the decontamination of probes and spacecrafts.     

An Experimental Study of the Effect of Vibrations on Supercritical Fluid Transfer Processes under Microgravity Conditions

On the basis of the data obtained in experiments onboard the Mirorbital complex (OC) in March and April 1999 with the ALICE-2 instrument, the influence of vibrations on heat propagation from a point-like source in the hexafluoride sulfur (SF₆) under supercritical parameters is analyzed. The appearance of two different heat propagation regimes is found: along and across the direction of vibrations. Upon the occurrence of the second-type regime, the heating region first stretches in the direction perpendicular to the direction of vibrations and then propagates at a rate typical for the undisturbed case. The temperature relaxation process is analyzed, which takes place near the heater after its turn-off. The relaxation rate grows as the intensity of vibrations increases and the initial temperature tends to the critical one. The determining dimensionless parameters of the problem are suggested.