Dynamics of Radiation Belt Particles

This paper reviews basic concepts of particle dynamics underlying theoretical aspect of radiation belt modeling and data analysis. We outline the theory of adiabatic invariants of quasiperiodic Hamiltonian systems and derive the invariants of particle motion trapped in the radiation belts. We discuss how the nonlinearity of resonant interaction of particles with small-amplitude plasma waves, ubiquitous across the inner magnetosphere, can make particle motion stochastic. Long-term evolution of a stochastic system can be described by the Fokker-Plank (diffusion) equation. We derive the kinetic equation of particle diffusion in the invariant space and discuss its limitations and associated challenges which need to be addressed in forthcoming radiation belt models and data analysis.     

Development Study on ATREX Engine

This is the status report of the development study on ATREX engine (Air Turbo Ramjet) that is now under way in the Institute of Space and Astronautical Science (ISAS) cooperation with the Ishikawajima Harima Heavy Industries (IHI), the Kawasaki Heavy Industries (KHI), the Mitsubishi Heavy Industries (MHI). ATREX engine will be applied for the propulsion system of fly-back booster of TSTO space plane. ATREX is the combined cycle (a fan-boosted ramjet) engine providing the effective thrust from sea level static to flight Mach number 6. ATREX is worked on the expander cycle with precooling the incoming air as shown in Fig. 1. ATREX employs the tip turbine configuration which allows the compactness and the light weight of turbo machinery and the variable geometry airintake and plugnozzle which allow the wide range operation conditions.From 1990 to 1992, “ ATREX-500“ has been tested at the sea level static conditions. ATREX-500 is the 1/4-scale model of which fan inlet diameter is 300 mm and overall length 2,200 mm. From 1992 have been performed the wind tunnel tests on the primary components of ATREX, the axisymmetric variable geometry airintakes, the precoolers and the variable geometry plug nozzles. In parallel to the windtunnel tests, the ram combusters have been tested simulating the hypersonic flight conditions and the application studies on advanced carbon-carbon composite for the tip-turbine and fan assembly has been proceeded.In 1994 initiated the flight test plan in which ATREX will be verified in the practical flight conditions by using an unmanned flying test bench.In 1995 will be tested ATREX-500 installing the precooler under the sea level static conditions to examine the engine performance and the icing on the precooler.The present paper addresses the high loading ram combuster experiment using the mixer with skewed lobes to generate swirl flow and the analytical studies and the designs on the precooler and the precooled ATREX engine and the flight test plan.     

Study of the seasonal ozone variations at European high latitudes

The geographic area at high latitudes beyond the polar circle is characterized with long darkness during the winter (polar night) and with a long summertime insolation (polar day). Consequentially, the polar vortex is formed and the surrounding strong polar jet is characterized by a strong potential vorticity gradient representing a horizontal transport barrier. The ozone dynamics of the lower and middle stratosphere is controlled both by chemical destruction processes and transport processes.     

Solar Surface Magnetism and Irradiance on Time Scales from Days to the 11-Year Cycle

The uninterrupted measurement of the total solar irradiance during the last three solar cycles and an increasing amount of solar spectral irradiance measurements as well as solar imaging observations (magnetograms and photometric data) have stimulated the development of models attributing irradiance variations to solar surface magnetism. Here we review the current status of solar irradiance measurements and modelling efforts based on solar photospheric magnetic fields. Thereby we restrict ourselves to the study of solar variations from days to the solar cycle. Phenomenological models of the solar atmosphere in combination with imaging observations of solar electromagnetic radiation and measurements of the photospheric magnetic field have reached high enough quality to show that a large fraction (at least, about 80%) of the solar irradiance variability can be explained by the radiative effects of the magnetic activity present in the photosphere. Also, significant progress has been made with magnetohydrodynamic simulations of convection that allow us to relate the radiance of the photospheric magnetic structures to the observations.     

Selection of the Mars Science Laboratory Landing Site

The selection of Gale crater as the Mars Science Laboratory landing site took over five years, involved broad participation of the science community via five open workshops, and narrowed an initial >50 sites (25 by 20?km) to four finalists (Eberswalde, Gale, Holden and Mawrth) based on science and safety. Engineering constraints important to the selection included: (1)?latitude (±30°) for thermal management of the rover and instruments, (2)?elevation (<?1?km) for sufficient atmosphere to slow the spacecraft, (3)?relief of <100–130?m at baselines of 1–1000?m for control authority and sufficient fuel during powered descent, (4)?slopes of <30° at baselines of 2–5?m for rover stability at touchdown, (5)?moderate rock abundance to avoid impacting the belly pan during touchdown, and (6)?a?radar-reflective, load-bearing, and trafficable surface that is safe for landing and roving and not dominated by fine-grained dust. Science criteria important for the selection include the ability to assess past habitable environments, which include diversity, context, and biosignature (including organics) preservation. Sites were evaluated in detail using targeted data from instruments on all active orbiters, and especially Mars Reconnaissance Orbiter. All of the final four sites have layered sedimentary rocks with spectral evidence for phyllosilicates that clearly address the science objectives of the mission. Sophisticated entry, descent and landing simulations that include detailed information on all of the engineering constraints indicate all of the final four sites are safe for landing. Evaluation of the traversabilty of the landing sites and target “go to” areas outside of the ellipse using slope and material properties information indicates that all are trafficable and “go to” sites can be accessed within the lifetime of the mission. In the final selection, Gale crater was favored over Eberswalde based on its greater diversity and potential habitability.     

The Solar Wind interactions with Lunar Magnetic Anomalies: A case study of the Chang’E-2 plasma data near the Serenitatis antipode

In this paper, we present the first and preliminary results on the near-Moon plasma environment, based on the spectrogram data obtained with the Solar Wind Ion Detector (SWID) onboard Chang’E-2 from four lunar orbits on 10–11 Oct 2010. These orbits, at a constant altitude of ∼100 km, approach gradually the Lunar Magnetic Anomaly (LMA) at the Serenitatis antipode. The data reveal tentatively a region with decrement in proton density and enhancement in temperature. The near coincidence of this region with the Serenitatis antipode probably suggests the presence of a minimagnetosphere associated with the LMA, which effectively shields and heats the incident Solar Wind (SW) protons.     

Comparison between HF propagation and DEMETER satellite measurements within the mid-latitude trough

The morphology of the auroral, sub-auroral and mid-latitude trough region of the ionosphere is strongly dependent on the interplanetary magnetic field and the level of geomagnetic activity. Changes in the morphology impact on the characteristics of HF signals propagating through these regions of the ionosphere. In order to develop a better understanding of these effects, a number of experiments have recently been undertaken in which the time of flight and direction of arrival of HF signals have been measured over several paths aligned along the mid-latitude trough. In addition, observations made by the DEMETER satellite of the mid-latitude trough electron density structure, dynamics and wave activity were used in order to investigate the effect of the fine structure of the ionosphere on HF signals. For two types of relatively common night time HF time of flight and azimuth of arrival behaviour (referred to here and elsewhere as ‘Type 1’ and ‘Type 2’ propagation), the signal behaviour is consistent with scatter from irregularities in the auroral region in the one case, and from irregularities present on the floor of the trough in the other.     

GPS sensing of precipitable water vapour during the March 2010 Melbourne storm

The March 2010 Melbourne storm is used as a case study to examine the potential of using Global Positioning System (GPS) observations for studying the precipitable water vapour (PWV) field. The Victorian statewide GPS infrastructure network, i.e. GPSnet, was used in this study. GPSnet is currently the only statewide and densest GPS infrastructure network in Australia, which provides an excellent opportunity to examine the distribution of water vapour as the severe weather system passed over the state. Data from 15 GPSnet stations were processed over a one-week period, i.e. a few days prior to and after the storm passage, during which the course of the storm extended from the west to the southeast corner of the state. In addition, data from two radiosonde sites of the Australian Bureau of Meteorology Upper Air Network were used to compare and validate the GPS derived PWV measurements. The findings demonstrate that there is strong spatial and temporal correlation between variations of the ground-based GPS-PWV estimates and the passage of the storm over the state. This is encouraging as the ground-based GPS water vapour sensing technique can be considered as a supplemental meteorological sensor in studying severe weather events. The advantage of using ground-based GPS-PWV technique is that it is capable of providing continuous observation of the storm passage with high temporal resolution. The spatial resolution of the distribution of water vapour is dependent on the geographical location and density of the GPS stations.     

Cosmic ray H/H ratio measured from BESS in 2000 during solar maximum

The Balloon-borne Experiment with a Superconducting Spectrometer (BESS) was flown from Lynn Lake, Manitoba, Canada in August, 2000, during the maximum solar modulation period, with an average residual atmospheric overburden of 4.3 g/cm². Precise spectral measurements of cosmic ray hydrogen isotopes from 0.178 GeV/n to 1.334 GeV/n were made during the 28.7 h of flight. This paper presents the measured energy spectra and their ratio, ²H/¹H. The results are also compared with previous measurements and theoretical predictions.