Satellite-based Experiment Research Articles

Indian Network for Space Weather Impact Monitoring (InSWIM): An initiative to observe and model the low latitude ionosphere over the Indian longitudes

The Space Physics Laboratory (SPL) of Vikram Sarabhai Space Centre (VSSC) has launched a science program called the Indian network for Space Weather Impact Monitoring (InSWIM) to monitor the effects of Space Weather events on the Indian low-latitude ionosphere-thermosphere system. This program aims to study the impact of Space weather on the Indian ionospheric region and develop an Ionospheric Model. The InSWIM network stations will be equipped with instruments such as Global Navigation Satellite Systems (GNSS) receivers, Low Earth Orbit (LEO) receivers, ionosondes, magnetometers, and airglow photometers/imagers. Currently, multi-frequency, multi-constellation GNSS Receiver systems are operational at various stations in India. This network will enable us to understand (a) the quiet-time variability of the ionosphere over the Indian low-latitude region, (b) comprehensively study the response of the low-latitude ionosphere specific to the Indian longitudes under different space weather conditions, with the goal of understanding the various physical mechanisms causing variability in the ionospheric regions, and (c) develop an ionospheric model to reduce ionospheric errors in GNSS systems. Additionally, this network will provide complementary information for rocket and satellite-based experiments. This paper aims to provide details of the InSWIM network to the scientific community for its possible use in monitoring and studying the impact of space weather on the near-Earth space environment.

Exploring the Influencing Factors in Identifying Soil Texture Classes Using Multitemporal Landsat-8 and Sentinel-2 Data

Soil texture is a key soil property driving physical, chemical, biological, and hydrological processes in soils. The rapid development of remote sensing techniques shows great potential for mapping soil properties. This study highlights the effectiveness of multitemporal remote sensing data in identifying soil textural class by using retrieved vegetation properties as proxies of soil properties. The impacts of sensors, modeling resolutions, and modeling techniques on the accuracy of soil texture classification were explored. Multitemporal Landsat-8 and Sentinel-2 images were individually acquired at the same time periods. Three satellite-based experiments with different inputs, i.e., Landsat-8 data, Sentinel-2 data (excluding red-edge parameters), and Sentinel-2 data (including red-edge parameters) were conducted. Modeling was carried out at three spatial resolutions (10, 30, 60 m) using five machine-learning (ML) methods: random forest, support vector machine, gradient-boosting decision tree, categorical boosting, and super learner that combined the four former classifiers based on the stacking concept. In addition, a novel SHapley Addictive Explanation (SHAP) technique was introduced to explain the outputs of the ML model. The results showed that the sensors, modeling resolutions, and modeling techniques significantly affected the prediction accuracy. The models using Sentinel-2 data with red-edge parameters performed consistently best. The models usually gave better results at fine (10 m) and medium (30 m) modeling resolutions than at a coarse (60 m) resolution. The super learner provided higher accuracies than other modeling techniques and gave the highest values of overall accuracy (0.8429), kappa (0.7611), precision (0.8378), recall rate (0.8393), and F1-score (0.8398) at 30 m with Sentinel-2 data involving red-edge parameters. The SHAP technique quantified the contribution of each variable for different soil textural classes, revealing the critical roles of red-edge parameters in separating loamy soils. This study provides comprehensive insights into the effective modeling of soil properties on various scales using multitemporal optical images.

Study of the performances of the DAMPE silicon-tungsten tracker after five years of mission

DAMPE (DArk Matter Particle Explorer) is a satellite-based experiment launched in December 2015 and smoothly taking data after five years of mission. The Silicon-Tungsten Tracker (STK) is characterized by 6 double layers of silicon micro-strip detectors, for a total detection area of 7 m2, and three 1 mm thick tungsten plates, placed in the mechanical support structure, aimed to the photon conversion in e± pairs. The STK has a double role: precise reconstruction of the track of charged particles with a spatial resolution around 40 μm for most incident angles of the incoming particles, identification of the charge of the incoming cosmic rays. The STK performances are excellent after five years of continuous operation in space: in this contribution the STK in-orbit calibration and performances during the whole DAMPE mission will be presented.

Axion gravitodynamics, Lense-Thirring effect, and gravitational waves

We investigate physical implications of a gravitational analog of axion electrodynamics with a parity-violating gravitoelectromagnetic theta term. This is related to the Nieh-Yan topological invariant in gravity with torsion, in contrast to the well-studied gravitational Chern-Simons term quadratic in curvature, coupled via a dynamical axionlike scalar field. Axion gravitodynamics is the corresponding linearized theory. We find that potentially observable effects are over 80 orders of magnitude stronger than for its Chern-Simons counterpart and could be in reach for detection by experiments in the near future. For a near-Earth scenario, we derive corrections to the Lense-Thirring effect and compare them to data from satellite-based experiments (Gravity Probe B). For gravitational waves, we find modified dispersion relations, derive the corresponding polarization-dependent modified group and phase velocities, and compare them to data from neutron star mergers (GW170817) to derive even stronger bounds.

Testing Gravitational Theories in the Field of the Earth with the SaToR-G Experiment

A new satellite-based experiment in the field of gravitation, SaToR-G, is presented. It aims to compare the predictions of different theories of gravitation in the limit of weak-field and slow-motion. The ultimate goal of SaToR-G is searching for possible “new physics” beyond General Relativity, which represent the state-of-the-art of our current knowledge of gravitational physics. A key role in the above perspective is the theoretical and experimental framework that confines our work. To this end, we will exploit as much as possible the classical framework suggested by R.H. Dicke over fifty years ago.

The MONICA Experiment for Investigating the Ion Composition of Solar Cosmic Rays

The MONICA satellite-based experiment is described. In this experiment, fluxes of cosmic-ray ions from H to Ni are investigated near the Earth in the energy range of 10–300 MeV/nucleon. The main scientific objectives of the MONICA experiment are to measure the ion and isotope compositions and the energy spectra of solar cosmic rays for individual solar events and to study the evolution of these characteristics over time. The MONICA experiment will help to investigate the ion and isotope composition of the anomalous component of cosmic rays, galactic cosmic rays, and nuclear fluxes in the Earth’s radiation belt. Observations of ion fluxes will be carried out using the MONICA high-aperture multilayer semiconductor spectrometer–telescope installed on board a spacecraft with a low-Earth circular polar orbit at a height of approximately 600 km. This orbit will make it possible to perform the method for measuring the charge of ions with energies above 10 MeV/nucleon, which is based on the use of the Earth’s magnetic field as a particle- charge separator. The geometric factor of the instrument is 100 cm2 sr and the angular resolution is 1°.

Universal extra dimensions and the graviton portal to dark matter

The Universal Extra Dimension (UED) paradigm is particularly attractive as it not only includes a natural candidate for the Dark Matter particle , but also addresses several issues related to particle physics. Non-observations at the Large Hadron Collider, though, has brought the paradigm into severe tension. However, a particular 5-dimensional UED model emerges from a six dimensional space-time with nested warping. The AdS6 bulk protects both the Higgs mass as well as the UED scale without invoking unnatural parameter values. The graviton excitations in the sixth direction open up new (co-)annihilation channels for the Dark Matter particle, thereby allowing for phenomenological consistency, otherwise denied to the minimal UED scenario. The model leads to unique signatures in both satellite-based experiments as well as the LHC.

Offline software for the DAMPE experiment**Supported by Chinese 973 Program (2010CB833002), the Strategic Priority Research Program on Space Science of the Chinese Academy of Science (CAS) (XDA04040202-4), the Joint Research Fund in Astronomy under cooperative agreement between the National Natural Science Foundation of China (NSFC) and CAS (U1531126) and 100 Talents Program of the Chinese Academy of Science

A software system has been developed for the DArk Matter Particle Explorer (DAMPE) mission, a satellite-based experiment. The DAMPE software is mainly written in C++ and steered using a Python script. This article presents an overview of the DAMPE offline software, including the major architecture design and specific implementation for simulation, calibration and reconstruction. The whole system has been successfully applied to DAMPE data analysis. Some results obtained using the system, from simulation and beam test experiments, are presented.

Landau-pomeranchuk-migdal air showers initiated by ultra-high-energy neutrinos and their detection in a satellite-based experiment

The ultra-high-energy (UHE) atmospheric showers with strong influence of the Landau-Pomeranchuk-Migdal (LPM) effect (here after LPM showers) are exclusively expected to be produced by UHE neutrinos. Studies on the characteristics of the LPM showers are essentially important to discriminate neutrino shower (which produced by neutrino interaction) from hadronic shower (initiated by primary hadron). We calculate the LPM showers initiated by electrons with energies of 1018 to 1021 eV, using the hybrid method as exactly as possible. Reflecting the change in the air density along the shower trajectories, the variety of the LPM-shower profiles is shown in different cases for their starting points in atmosphere. Through the study of time profiles of air fluorescent photon components from the LPM showers, the detection capability of UHE neutrinos has also been investigated by the satellite-based experiment with a large acceptance, e.g., the TUS experiment.

AN EMPIRICAL MODEL OF PRODUCTION AND ATTENUATION OF FLUORESCENCE LIGHT IN ATMOSPHERE FOR SATELLITE-BASED ULTRA HIGH ENERGY COSMIC RAY EXPERIMENTS

In the context of detection of Ultra High Energy Cosmic Ray (UHECR) showers from space the details of fluorescence light production and transmission in the atmosphere are given. An analytical model of the fluorescence yield, in dependence on nitrogen molecular parameters and the atmospheric conditions, is presented. Seasonal and geographical variations of the total fluorescence photon yield between 300 nm and 400 nm in air excited by 0.85 MeV electrons are shown as a function of the altitude, using different atmospheric models. In the frame of a satellite-based UHECR experiment the fluorescence yield has been corrected by the overall atmospheric transmission which takes into account, in the simplest approximation, the wavelength-dependent scattering and absorption of the fluorescence light from air molecules, from stratospheric ozone, and from aerosol. The effect of the atmospheric attenuation on the fluorescence yield is shown as a function of the altitude of the emission point of light.

A technique for identifying nuclei in the MONICA experiment

We discuss the results of comparison and optimization of (ΔE − E) methods for identifying nuclei with the aid of a multilayer Si detector that will be used in the MONICA satellite-based experiment aimed at studying the nuclear component of cosmic rays from hydrogen to nickel in the energy range of 10–300 MeV/nucleon. The residual-range and Bethe-Bloch curve approximation methods are considered. Using the GEANT4 simulation, it is shown that the Bethe-Bloch curve approximation method not only ensures a better mass resolution (which is particularly important for identification of heavy nuclei), but also provides a means for identifying “drift” nuclei with satisfactory charge (<0.3) and energy (<3%) resolutions. The results can be used to prepare new experiments in which (ΔE − E) nuclear identification methods are expected to be employed.

Is the PAMELA positron excess winos?

Recently the PAMELA satellite-based experiment reported an excess of galactic positrons that could be a signal of annihilating dark matter. The PAMELA data may admit an interpretation as a signal from a winolike lightest supersymmetric particle of mass about 200 GeV, normalized to the local relic density, and annihilating mainly into $W$ bosons. This possibility requires the current conventional estimate for the energy loss rate of positrons to be too large by roughly a factor of 5. Data from antiprotons and gamma rays also provide tension with this interpretation, but there are significant astrophysical uncertainties associated with their propagation. It is not unreasonable to take this well-motivated candidate seriously, at present, in part because it can be tested in several ways soon. The forthcoming PAMELA data on higher energy positrons and the Fermi Gamma-ray Space Telescope (formerly the Gamma-ray Large Area Space Telescope) data should provide important clues as to whether this scenario is correct. If correct, the wino interpretation implies a cosmological history in which the dark matter does not originate in thermal equilibrium.

Constraining supersymmetry from the satellite experiments

In this paper I study the detectability of $\ensuremath{\gamma}$ rays from dark matter annihilation in the subhalos of the Milky Way by the satellite-based experiments EGRET and GLAST. I work in the frame of supersymmetric extension of the standard model and assume the lightest neutralino being the dark matter particles. Based on the N-body simulation of the evolution of dark matter subhalos I first calculate the average intensity distribution of this new class of $\ensuremath{\gamma}$-ray sources by neutralino annihilation. It is possible to detect these $\ensuremath{\gamma}$-ray sources by EGRET and GLAST. Conversely, if these sources are not detected the nature of the dark matter particles will be constrained by these experiments, depending, however, on the uncertainties of the subhalo profile.

Angular signatures of dark matter in the diffuse gamma ray background

Dark matter annihilating in our galaxy’s halo and elsewhere in the universe isexpected to generate a diffuse flux of gamma rays, potentially observable with nextgeneration satellite-based experiments, such as GLAST. In this paper, we studythe signatures of dark matter in the angular distribution of this radiation, inparticular the deterministic ones. We discuss the effect, pertaining to the extragalacticcontribution, of the motion of the solar system with respect to the cosmological restframe, and anisotropies due to the structure of our local universe. For the gammaray flux from dark matter in our own galactic halo, we discuss the effects of theoffset position of the solar system, the Compton–Getting effect, the asphericity ofthe Milky Way halo, and the signatures of nearby substructure. We explore theprospects for the detection of these features by the GLAST satellite and find that, if∼10% or more of the diffuse gamma ray background observed by EGRET is the result of darkmatter annihilations, then GLAST should be sensitive to anisotropies at the sub-per centlevel. Such precision would be sufficient to detect many, if not all, of the signaturesdiscussed in this paper.

Reduced Charge Diffusion in Thick, Fully Depleted CCDs With Enhanced Red Sensitivity

Lateral charge diffusion in charge-coupled devices (CCDs) dominates the device point-spread function (PSF), which can affect both image quality and spectroscopic resolution. We present new data and theoretical interpretations for lateral charge diffusion in thick, fully depleted CCDs developed at Lawrence Berkeley National Laboratory (LBNL). Because they can be overdepleted, the LBNL devices have no field-free region and diffusion is controlled through the application of an external bias voltage. Recent improvements in CCD design at LBNL allow the application of bias voltages exceeding 200 V. We give results for a 3512times3512 format, 10.5 mum pixel back-illuminated p-channel CCD developed for the SuperNova/Acceleration Probe (SNAP), a proposed satellite-based experiment designed to study dark energy. Lateral charge diffusion, which is well described by a symmetric two-dimensional (2-D) Gaussian function, was measured at substrate bias voltages between 3 and 115 V. At a bias voltage of 115 V, we measure a root-mean square (rms) diffusion of 3.7plusmn0.2mum. Lateral charge diffusion in LBNL CCDs will meet the SNAP requirements

Radiation-tolerant, red-sensitive CCDs for dark energy investigations

We describe the development of thick (200–300 μm), fully depleted p-channel, charge-coupled devices (CCDs). The advantages of these CCDs relative to conventional thin, n-channel CCDs include: high quantum efficiency over a wide range of wavelengths, extending into the near-infrared; negligible fringing at long (∼900–1000 nm) wavelengths; improved radiation tolerance; and a small point-spread function controlled through the application of the bias voltage. These visible-to-near-infrared light detectors are good candidates for the next generation of large focal-plane mosaics under development for dark energy measurements. The Dark Energy Survey has selected these CCDs for the focal plane of a new camera being designed for the Blanco 4 m telescope at CTIO in Chile. They also meet all the requirements for the visible-light detectors for the SuperNova/Acceleration Probe, a satellite-based experiment designed to make precision measurements of dark energy.

The LPM showers traversing the atmosphere

We simulate the LPM showers due to Extremely-High-Energy(EHE) neutrinos traversing atmosphere horizontally without colliding with the Earth. We calculate the LPM showers with energies of 1017eV to 1022eV, using the hybrid method as exactly as possible. Reffecting the complicated change in the air density along the trajectories of the shower developments, the variety of the LPM showers is shown to depend on their starting points and their heights. The EHE LPM showers in atmosphere are exclusively produced by EHE neutrinos. Therefore, the studies on the LPM showers are very important for EHE neutrino astrophysics. As an example, the air fluorescence photon profiles of the LPM showers are also given for the future satellite-based experiment.

STATUS AND PERSPECTIVES OF GLAST GAMMA RAY EXPERIMENT

GLAST, the Gamma-ray Large Area Telescope, is a satellite-based experiment able to measure the cosmic gamma-ray flux in the energy range between 20 MeV and 300 GeV or above. The sensitivity is more than 30 times respect to EGRET and the good spatial and time resolution over a large field of view let us to cover a large variety of high energy phenomena. In particular GLAST will be able to study both diffuse emission and point-like gamma ray sources, including active galactic nuclei, gamma ray bursts, pulsars and supernova remnants. In addition, the potentialities of GLAST to explore rare or exotic phenomena like supersymmetric dark matter annihilations will be shown. The present knowledge of the science opportunities that the GLAST experiment can explore will be completed with the detector description and the current status of the experiment.

Prospects for observing dark-matter remnants with GLAST

The satellite-based experiment, GLAST (Gamma-ray Large Area Space Telescope), is under construction and is planned to measure the cosmic γ-ray flux in the energy range 20 MeV to >300 GeV, with supporting measurements for γ-ray bursts from 10 keV to 25 MeV. With its launch in 2007, GLAST will open a new and important window on a wide variety of high-energy phenomena, including exotic relics from the Big Bang. Among these may be the decay/annihilation products of the hypothesized super symmetric image of the known particles. Single-photon energy thresholds for channels leading to such final states have been excluded in a model-dependent manner by accelerator searches to energies greater than 50 GeV. The ability of GLAST to set limits on this important component of cosmological evolution is presented along with an update on the present status of this mission.

Probing radiative solar neutrino decays

Motivated by a pilot experiment conducted by F.Vannucci et al. during a solar eclipse, we work out the geometry governing the radiative decays of solar neutrinos. Surprisingly, although a smaller proportion of the photons can be detected, the case of strongly non-degenerate neutrinos brings better limits in terms of the fundamental couplings. We advocate satellite-based experiments to improve the sensitivity.