Pre-storm behaviour of NmF2 and TEC (GPS) over equatorial and low latitude stations in the Indian sector

The pre-storm behavior of NmF₂ and TEC over an equatorial station, Trivandrum (8.47°N, 76.91°E, dip 0.6°S) and a low latitude station, Waltair (17.7°N,83.3°E, dip 20°N) has been studied for a total of 18 strong geomagnetic storms with DST ? −100 nT. The simultaneous measurements of GPS-TEC and NmF₂ over Trivandrum and Waltair during the period 2000–2005 have been considered for the present study. It is found that there is a substantial increase in NmF₂ and TEC before the onset of the storm over Waltair, while the increase is not present at Trivandrum. The origin of pre-storm enhancements in electron density still remains unresolved owing to several conditions in their potential sources and occurrence mechanisms. In the present study an attempt is made to identify the possible mechanisms responsible for such enhancements in electron density of the F-region.     

Does the endolymph pass through the base of the cupula?

Whether the endolymph of the semicircular canal passes the cupular partition or not was examined using the lateral semicircular canal system of adult pigeons (Columba livia). By applying various pressures by means of injection of a dye solution through the membranous canal, it was found that the dye solution, was seen to pass the cupula even under very low pressures when the pressure was increased gradually. When pulled by a magnet, the ultrafine particles of the dextran magnetite contained in the injected fluid were found to pass through the subcupular space without evident increase of the ampullary pressure.     

Strategies for telecommunications and navigation in support of Mars exploration

The planned exploration of Mars will pose new and unique telecommunications and navigation challenges. The full range of orbital, atmospheric, and surface exploration will drive requirements on data return, energy-efficient communications, connectivity, and positioning. In this paper we will summarize the needs of the currently planned Mars exploration mission set, outline design trades and options for meeting these needs, and quantify the specific telecommunications and navigation capabilities of an evolving infrastructure.     

Updated Review of Planetary Atmospheric Electricity

This paper reviews the progress achieved in planetary atmospheric electricity, with focus on lightning observations by present operational spacecraft, aiming to fill the hiatus from the latest review published by Desch et al. (Rep. Prog. Phys. 65:955–997, 2002). The information is organized according to solid surface bodies (Earth, Venus, Mars and Titan) and gaseous planets (Jupiter, Saturn, Uranus and Neptune), and each section presents the latest results from space-based and ground-based observations as well as laboratory experiments. Finally, we review planned future space missions to Earth and other planets that will address some of the existing gaps in our knowledge.     

On the different approaches of Rayleigh optical depth determination

Rayleigh optical depth is an integral part of many radiative transfer problems. This paper discusses different elements and approaches of its determination. Then, it presents a method, which ensures more realistic estimate of Rayleigh optical depth by using refractive index and depolarization factor (including rotational Raman lines) adjusted according to the state and composition of the atmosphere. It is based on the published experimental and theoretical results. The Rayleigh optical depth calculations are compared with the Elterman’s model calculations for trend analysis purpose. Rayleigh optical depths are found to be around 3.4% lower than previous researchers, as they ignored the constraints of conservation of angular momentum in the rotational/vibrational transitions of the molecules during scattering.     

The Dynamic Heliosphere: Outstanding Issues

Properties of the heliospheric interface, a complex product of an interaction between charged and neutral particles and magnetic fields in the heliosphere and surrounding Circumheliospheric Medium, are far from being fully understood. Recent Voyager spacecraft encounters with the termination shock and their observations in the heliosheath revealed multiple energetic particle populations and noticeable spatial asymmetries not accounted for by the classic theories. Some of the challenges still facing space physicists include the origin of anomalous cosmic rays, particle acceleration downstream of the termination shock, the role of interstellar magnetic fields in producing the global asymmetry of the interface, the influence of charge exchange and interstellar neutral atoms on heliospheric plasma flows, and the signatures of solar magnetic cycle in the heliosheath. These and other outstanding issues are reviewed in this joint report of working groups 4 and 6.     

Equivalent Electric Circuit Models of Coronal Magnetic Loops and Related Oscillatory Phenomena on the Sun

Coronal loops, which trace closed magnetic field lines, are the primary structural elements of the solar atmosphere. Complex dynamics of solar coronal magnetic loops, together with action of possible subphotospheric dynamo mechanisms, turn the majority of the coronal loops into current-carrying structures. In that connection none of the loops can be considered as isolated from the surroundings. The current-carrying loops moving relative to each other interact via the magnetic field and currents. One of the ways to take into account this interaction consists in application of the equivalent electric circuit models of coronal loops. According to these models, each loop is considered as an equivalent electric LCR-circuit with variable inductive coefficients L, capacitance C, and resistance R, which depend on shape, scale, position of the loop with respect to neighbouring loops, as well as on the plasma parameters in the magnetic tube. Such an approach enables to describe the process of electric current dynamics in the groups of coronal loops, as well as the related dynamical, energy release and radiation processes. In the present paper we describe the major principles of LCR-circuit models of coronal magnetic loops, and show their application for interpretation of the observed oscillatory phenomena in the loops and in the related radiation.     

Method for the annular gas-liquid mixture flow regime in a vertical cylindrical channel

A mathematical model for the annular gas-liquid mixture flow in the cylindrical channel is described. The influence of an upward turbulent gas flow on the downward liquid film is considered. The problem is numerically solved and the calculation results are compared with the experimental data.