Airglow monitoring by one-pixel detector Mackovjak, Š.; Bobík, P.; Baláž, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2019, Letnik:
922
Journal Article
Recenzirano
The night time airglow is a dynamic phenomenon that acts as a background for the detection of the extensive air shower (EAS) fluorescence. It is a mandatory task to monitor this background for the ...ground-based telescopes and for the planned space-based telescopes, dedicated to observe the EAS events induced by the ultra-high energy cosmic rays. To perform this task, we have developed a one-pixel Airglow MONitor (AMON) instrument. This instrument provides the absolute intensities of the measured night sky background in the near-ultraviolet spectral range and in the one second temporal resolution. It is designed to be easily operated in different locations and so to offer required spatial resolution. The first results demonstrate that AMON data might be useful not only for the high-energy astrophysics purposes, but also for the studies of the airglow dynamics.
The energetic particle experiment MEP-2 onboard the Spectr-R high apogee satellite is briefly described. The instrument measures fluxes and spectra of electrons (30 keV–350 keV) and ions (30 ...keV–3.2MeV), using two pairs of silicon detectors. The example of first observations upstream from the bow shock illustrates its successful operation in space. Unique observations of ∼30 s strong fluctuations of energetic ions with energies up to two hundred keV are discussed.
The ESA-JAXA BepiColombo mission to Mercury will provide simultaneous
measurements from two spacecraft, offering an unprecedented opportunity to investigate
magnetospheric and exospheric particle ...dynamics at Mercury as well as their interactions
with solar wind, solar radiation, and interplanetary dust. The particle instrument suite SERENA
(Search for Exospheric Refilling and Emitted Natural Abundances) is flying in space
on-board the BepiColombo Mercury Planetary Orbiter (MPO) and is the only instrument for
ion and neutral particle detection aboard the MPO. It comprises four independent sensors:
ELENA for neutral particle flow detection, Strofio for neutral gas detection, PICAM for
planetary ions observations, and MIPA, mostly for solar wind ion measurements. SERENA
is managed by a System Control Unit located inside the ELENA box. In the present paper
the scientific goals of this suite are described, and then the four units are detailed, as well
as their major features and calibration results. Finally, the SERENA operational activities
are shown during the orbital path around Mercury, with also some reference to the activities
planned during the long cruise phase.
Abstract
Mercury’s southern inner magnetosphere is an unexplored region as it was not observed by earlier space missions. In October 2021, BepiColombo mission has passed through this region during ...its first Mercury flyby. Here, we describe the observations of SERENA ion sensors nearby and inside Mercury’s magnetosphere. An intermittent high-energy signal, possibly due to an interplanetary magnetic flux rope, has been observed downstream Mercury, together with low energy solar wind. Low energy ions, possibly due to satellite outgassing, were detected outside the magnetosphere. The dayside magnetopause and bow-shock crossing were much closer to the planet than expected, signature of a highly eroded magnetosphere. Different ion populations have been observed inside the magnetosphere, like low latitude boundary layer at magnetopause inbound and partial ring current at dawn close to the planet. These observations are important for understanding the weak magnetosphere behavior so close to the Sun, revealing details never reached before.
► First-time use of ESA’s Mars Energetic Radiation Environment Models/MEREM to estimate the radiation hazard at three prospective landing sites. ► These sites display significantly different ...hydrological conditions/soil compositions. The surface radiation environments predicted are shown to vary with epoch and landing site. ► The Effective Dose (ED) does not depend on location but the Ambient Dose Equivalent (ADE) does. ► MEREM’s dose predictions are in general agreement with those of NASA’s Heavy Ion-Nucleon Transport Code for Space Radiation/HZETRN. ► The Martian atmosphere provides sufficient shielding to maintain dose levels below currently accepted exposure limits over short (30 days) surface stays.
The ‘Mars Energetic Radiation Environment Models’ (dMEREM and eMEREM) recently developed for the European Space Agency are herein used to estimate, for the first time, background Galactic Cosmic Ray (GCR) radiation and flare related solar energetic particle (SEP) events at three candidate martian landing sites under conditions where particle arrival occurred at solar minimum (December, 2006) and solar maximum (April, 2002) during Solar Cycle 23. The three landing sites were selected on the basis that they are characterized by significantly different hydrological conditions and soil compositions. Energetic particle data sets recorded on orbit at Mars at the relevant times were incomplete because of gaps in the measurements due to operational constraints. Thus, in the present study, comprehensive near-Earth particle measurements made aboard the GOES spacecraft were used as proxies to estimate the overall particle doses at each perspective landing site, assuming in each case that the fluxes fell off as 1/r2 (where r is the helio-radial distance) and that good magnetic connectivity always prevailed. The results indicate that the particle radiation environment on Mars can vary according to the epoch concerned and the landing site selected. Particle estimations obtained using MEREM are in reasonable agreement, given the inherent differences between the models, with the related NASA Heavy Ion–Nucleon Transport Code for Space Radiation/HZETRN. Both sets of results indicated that, for short (30days) stays, the atmosphere of Mars, in the cases of the SEPs studied and the then prevailing background galactic cosmic radiation, provided sufficient shielding at the planetary surface to maintain annual skin and blood forming organ/BFO dose levels below currently accepted ionizing radiation exposure limits. The threat of occurrence of a hard spectrum SEP during Cruise-Phase transfers to/from Mars over 400days, combined with the associated cumulative effect of prolonged GCR exposure, poses an as yet unsolved hazard to prospective onboard personnel.
Comprehensive records are available in ENA data of ring current activity recorded by the NUADU instrument aboard TC-2 on 15 May, 2005 during a major magnetic storm （which incorporated a series of ...substorms）. Ion fluxes at 4-min temporal resolution derived from ENA data in the energy ranges 50-81 and 81-158 keV are compared with in situ particle fluxes measured by the LANL-SOPA instruments aboard LANL-01, LANL-02, LANL-97, and LANL-84 （a series of geostationary satellites that encircle the equatorial plane at -6.6 RE）. Also, magnetic fields measured simultaneously by the magetometers aboard GOES-10 and GOES-12 （which are also geostationary satellites） are compared with the particle data. It is demonstrated that ion fluxes in the ring current were enhanced during geomagnetic field tailward stretching in the growth phases of substorms rather than after Earthward directed dipolarization events. This observation, which challenges the existing concept that ring current particles are injected Earthward from the magnetotail following dipolarization events, requires further investigation using a large number of magnetic storm events.
The second-order analysis is used to examine the laced built-up member with two extruded I-sections under combined compression and bending. The member bottom end is fixed, and the upper one is free ...in the case of in-plane buckling. The member is restrained against out-of-plane buckling at both ends. The global initial sway imperfection is taken into account instead of the local bow imperfection.
The Slovac Republic Repository of Radioactive Waste (radwaste) in place Mochovce presents a multi-barrier repository of the surface type designed as an ultimate storage of treated solid and fixed, ...low-and very low-level radwaste generated during the operation and decommissioning of the nuclear power plants, in research institutes, laboratories and hospitals in the Slovak Republic The isolation of the radwaste and retardation of the radionuclides are provided by the barrier system of the repository. To assess the complete system and parts of one of the most important barriers-the multi-barrier ultimate shielding of the repository-the model of the ultimate shielding of the repository was designed. The monitoring results of the model "in situ" will be applicable for projecting the ultimate shielding of the repository.
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