Microwave burst of November 17, 1991: Evidence of fragmented particle injection into a coronal loop

The unusual event of November 17, 1991 07:04 UT, observed at 2.5 and 2.85 GHz, is analysed. The event reveals the sophisticated superfine time structure including sudden reductions and quasi-periodic pulsations. We shown that the sudden reductions (30–100 ms) can be driven by upward injected 100 keV electron beams filling the losscone of the coronal magnetic trap. The nonlinear oscillations of Langmuir waves provide the best fit for the pulsation observed. A reduced steady-state level of the pulsation phase is connected with quasi-continuous injection of electrons. The physical parameters of the radio source are found for the event.     

One-up on L1: Can X-rays provide longer advanced warning of solar wind flux enhancements than upstream monitors?

Observations of strong solar wind proton flux correlations with ROSAT X-ray rates along with high spectral resolution Chandra observations of X-rays from the dark Moon show that soft X-ray emission mirrors the behavior of the solar wind. In this paper, based on an analysis of an X-ray event observed by XMM-Newton resulting from charge exchange of high charge state solar wind ions and contemporaneous neutral solar wind data, we argue that X-ray observations may be able to provide reliable advance warning, perhaps by as much as half a day, of dramatic increases in solar wind flux at Earth. Like neutral atom imaging, this provides the capability to monitor the solar wind remotely rather than in situ.     

Did life exist on Mars? Search for organic and inorganic signatures, one of the goals for “SAM” (sample analysis at Mars)

Observation of Mars shows signs of a past Earth-like climate, and, in that case, there is no objection to the possible development of life, in the underground or at the surface, as in the terrestrial primitive biosphere. Sample analysis at Mars (SAM) is an experiment which may be proposed for atmospheric, ground and underground in situ measurements. One of its goals is to bring direct or indirect information on the possibility for life to have developed on Mars, and to detect traces of past or present biological activity. With this aim, it focuses on the detection of organic molecules: volatile organics are extracted from the sample by simple heating, whereas refractory molecules are made analyzable (i.e. volatile), using derivatization technique or fragmentation by pyrolysis. Gaseous mixtures thus obtained are analyzed by gas chromatography associated to mass spectrometry. Beyond organics, carbonates and other salts are associated to the dense and moist atmosphere necessary to the development of life, and might have formed and accumulated in some places on Mars. They represent another target for SAM. Heating of the samples allows the analysis of structural gases of these minerals (CO₂ from carbonates, etc.), enabling to identify them. We also show, in this paper, that it may be possible to discriminate between abiotic minerals, and minerals (shells, etc.) created by living organisms.     

CME-geometry and cosmic-ray anisotropy observed by a prototype muon detector network

We analyze the cosmic-ray anisotropy observed by a prototype network of muon detectors during geomagnetic storms associated with coronal mass ejections (CMEs). The network currently consists of multidirectional surface muon detectors at Nagoya (Japan) and Hobart (Australia), together with a prototype detector at São Martinho (Brazil) which has been in operation since March, 2001. In this report, we analyze the anisotropy recorded in both the muon detector and neutron monitor (the Spaceship Earth) networks and find significant enhancements of cosmic-ray anisotropy during geomagnetic storms. Following the analysis by Bieber and Evenson [Bieber, J.W., Evenson, P. CME geometry in relation to cosmic ray anisotropy. Geophys. Res. Lett. 25 (1998) 2955–2958] for the neutron monitor data at 10 GeV, we also derive cosmic-ray density gradients from muon data at higher-energy (50 GeV), possibly reflecting the larger-scale geometry of CMEs causing geomagnetic storms. We particularly find in some events the anisotropy enhancement clearly starting prior to the storm onset in both the muon and neutron data. This is the first result of the CME-geometry derived from simultaneous observations of the anisotropy with networks of multidirectional muon detectors and neutron monitors.     

Results of cosmic radiation dose field measurements aboard the “Salyut-6” orbital station

During the 3rd main expedition on board the “Salyut-6” orbital station in 1979 the integral characteristics of cosmic radiation were measured in various positions inside the manned modules (experiment “Integral”). Measurements were performed with thermoluminescent dosimeters, photographic films and solid state plastic detectors supplied for the experiment by specialists of the USSR, Bulgaria, Hungary, GDR and Romania. The dose gradient inside the manned modules of the station amounted to 70 % for long intervals of time. During the experimental period the dose rate inside the station was 15 to 30 mrad per day. The mean flux of particles with z 6 and LET 200 keV/μm was found to be 0.22 cm⁻² day⁻¹.     

Optical search for gamma-ray bursts

The preliminary results from optical search for light pulses associated with gamma ray bursts by means of the Czechoslovak Fireball Network plate collection at the Ondřejov observatory are given. Optical monitoring represents more than 7700 hours, but no real optical counterpart was found. Problems associated with the optical search for gamma ray bursts are discussed.     

Energy requirement of magnetic reconnection during magnetospheric substorms

Methods are discussed to estimate energy transfer from the solar wind to the magnetosphere during substorm growth phases. Observational and modeling constraints are then used to assess quantitatively the total amount of energy stored in the magnetotail. The major avenues of energy dissipation are examined and the energy that is released in the form of plasma sheet heating, ionospheric Joule heating, plasmoids, and energetic particle production during substorms is assessed. Energy sources are evaluated to drive substorm evolution in a particularly well-observed case: stored tail-lobe energy is sufficient to drive observed substorm dissipation processes (by large margins). On the other hand, energy in the closed field lines of the plasma sheet is insufficient to supply the substorm energy. Hence, magnetic reconnection is required on energy grounds during well-observed substorm cases.     

The energy release of substorm and magnetic storm: Its present state and future improvements by KuaFu mission

Considering the KuaFu mission, state of the energy release of substorm and storm is simply presented and it’s improvements by KuaFu mission are investigated. The KuaFu mission will provide us an opportunity to improve our understanding of the energy release during the storm and the substorms. The two KuaFu-B satellites flying in 180° phase-lagged formation in a polar orbit will allow synoptic observations of the auroral oval, central plasma sheet, ring current and other regions. It can monitor the polar region 24/7 continuously. The advantage of the KuaFu mission is to provide the data during all phases of storm and substorm time that can be used to study the global energy release during all phases continuously. The data from auroral imager and other in-situ instruments on board KuaFu-B can be used to study the auroral dynamics and Joule heating during a storm and substorm. The data from the neutral atom imager instrument can be used to study the dynamics and the energy release in the ring current region from sudden commencement to complete storm recovery. Furthermore the data from KuaFu-A, which is around L1 point, can be used to study the interplanetary conditions along with the data from the plasma sheet to study the triggering process and energy release during a substorm. So, KuaFu mission with its continuous time monitoring facilities would enable us to make much progress towards solving the underlying problems.     

DTFT-based frequency lock loop for GNSS applications

A frequency lock loop (FLL) for Global Navigation Satellite System (GNSS) applications is described here. The core element is the discrete time Fourier transform (DTFT), that leads to a maximum likelihood (ML) frequency estimation and can be conveniently implemented in a software defined radio (SDR) HW platform. The algorithm is based on the iterative evaluation of DTFTs in a single frequency until the incoming frequency is locked.     

Space weather and commercial airlines

Space weather phenomena can effect many areas of commercial airline operations including avionics, communications and GPS navigation systems. Of particular importance at present is the recently introduced EU legislation requiring the monitoring of aircrew radiation exposure, including any variations at aircraft altitudes due to solar activity. With the introduction of new ultra-long-haul “over-the-pole” routes, “more-electric” aircraft in the future, and the increasing use of satellites in the operation, the need for a better understanding of the space weather impacts on future airline operations becomes all the more compelling. This paper will present the various space weather effects, some provisional results of an ongoing 3-year study to monitor cosmic radiation in aircraft, and conclude by summarising some of the identified key operational issues, which must be addressed, with the help of the science community, if the airlines want to benefit from the availability of space weather services.