variations of the atmospheric chemical composition in the earths’s polar regions after solar proton flare on July 14, 2000 (photochemical simulation)

Altitude—temporal cross-sections q(z, t) of atmospheric ionization rates by solar protons above the polar regions were calculated using the GOES-10 satellite data on solar proton fluxes for the period of solar proton flare (SPF) on July 14, 2000. The values of q(z, t) were used further in calculations of variations of the atmospheric chemical composition during the flare in the northern and southern polar regions (70°N and 70°S) by two different 1D photochemical models of the atmosphere (neutral and charged components). The calculation results have shown considerable variation of the ozone content after SPF: a decrease of [O3] was about 80% at altitudes of 65–75 km above northern and 25% in the layer of 55–65 km above the southern polar region. Such decrease of the ozone content is a result of reactions with [NO] and [OH] whose concentrations have grown substantially during SPF. According to calculations, the increase of electron concentration during SPF has reached 3–4 orders of magnitude at altitudes of 50–80 km. A comparison of the calculation results with the observational data on [NO], [NO2], and [O3] from the UARS and HALOE satellites for 70°N have shown a good qualitative correspondence, however, for variations of nitric oxides there are quantitative discrepancies.     

Periodic solutions in three-dimensional restricted three-body problem: 2. Loss of symmetry at the 1:1 resonance

Within the framework of the circular restricted three-body problem a family of inverse periodic orbits around the two attracting bodies (the Egorov’s family) and families generated by it at the 1:1, 2:1, and 3:1 resonances for three-dimensional orbits in the Sun-Earth and Earth-Moon systems are considered. Their relationship with families generated by orbits around the libration points L ₁, L ₂ and L ₃ is investigated. One of the families contains periodic solutions that seem promising as possible orbits for the space radio telescope of the Millimetron project.     

A system of flight data acquisition,processing, and recording

A system for recording and analysis of flight information including the technical condition of a control object and the state of its controller’s health in real time aboard a flight vehicle and in ground-based air traffic control centers is described.     

On bandwidth of solar subsecond bursts in cm-range

The goal is to study parameters of drifting type III bursts, and find out the emission mechanism of these bursts and understand what factors affect instantaneous spectral bandwidth of these bursts.     

Plasma sheet oscillations and their relation to substorm development: Cluster and double star TC1 case study

We examined two consecutive plasma sheet oscillation and dipolarization events observed by Cluster in the magnetotail, which are associated with a pseudo-breakup and a small substorm monitored by the IMAGE spacecraft. Energy input from the solar wind and an associated enhancement of the cross-tail current lead to current sheet thinning and plasma sheet oscillations of 3–5 min periods, while the pseudo-breakups occur during the loading phase within a spatially limited area, accompanied by a localized dipolarization observed by DSP TC1 or GOES 12. That is, the so-called “growth phase” is a preferable condition for both pseudo-breakup and plasma sheet oscillations in the near-Earth magnetotail. One of the plasma sheet oscillation events occurs before the pseudo-breakup, whereas the other takes place after pseudo-breakup. Thus there is no causal relationship between the plasma sheet oscillation events and pseudo-breakup. As for the contribution to the subsequent small substorm, the onset of the small substorm took place where the preceding plasma sheet oscillations can reach the region.     

Theory of LDV Tracking Systems

The application of frequency-tracking systems to the analysis of laser doppler velocimeter (LDV) signals degraded by background noise has been studied both theoretically and experimentally. Expressions are derived for both the correlation function and the expected value of the phase derivative in the general case of noise off center from the Doppler frequency, and these results are specialized to specific cases of practical interest. Laboratory measurements of output signal-to-noise ratio (SNR) and dc error, for varying input SNR and noise center frequency offset, show good agreement with the theoretical predictions.     

Comparative Utilization of Limited Energy for Continuous and Pulse Operations

Comparative utilization of a limited amount of energy for continuous and pulse operations was investigated. Under a restriction that the amount of available energy was limited, general equations for operational hours of the energy source for given power output were derived for both continuous and pulse mode operations. This paper points out that due to various adjustable parameters available for pulse mode operation, if properly designed pulse mode operation produces longer utilization of available energy for required output power than continuous mode operation.     

Radiative and dynamical impacts of Arctic and Antarctic ozone holes: General circulation model experiments

Radiative and dynamical impacts of Arctic and Antarctic ozone holes on the general circulation are investigated with the aid of a general circulation model developed at Kyushu University. The model includes a simplified ozone photochemistry interactively coupled with radiation and dynamics. Resultant temperature structure consisting of a cooling in the polar lower stratosphere and a warming in the polar upper stratosphere brings about the intensification of the polar night jet. The cooling is caused by the decrease of solar ultraviolet heating due to the ozone depletion, while the warming is caused by adiabatic heating due to the enhancement of downward motion.     

Aperture Synthesis for Ionospherically Propagated HF Radio Signals

A high-frequency (HF) aperture was synthesized by receiving ionospherically propagated signals in an airplane. The signals used the one-hop F lower ray mode to propagate a distance of 2600 km and were processed to yield equivalent aperture lengths of 10 km and 70 km. It was shown that apertures of up to 10 km in length could sometimes achieve their ideal free-space directivity without use of ionospheric compensation.