Temperatures in the Upper Mesosphere and Lower Thermosphere from O2 Atmospheric Band Emission Observed by ICON/MIGHTIStevens, M. H.; Englert, C. R.; Harlander, J. M.; Marr, K. D.; Harding, B. J.; Triplett, C. C.; Mlynczak, M. G.; Yuan, T.; Evans, J. S.; Mende, S. B.; Immel, Thomas J.
doi: 10.1007/s11214-022-00935-xpmid: N/A
The Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) was launched aboard NASA’s Ionospheric Connection (ICON) Explorer satellite in October 2019 to measure winds and temperatures on the limb in the upper mesosphere and lower thermosphere (MLT). Temperatures are observed using the molecular oxygen atmospheric band near 763 nm from 90–127 km altitude in the daytime and 90–108 km in the nighttime. Here we describe the measurement approach and methodology of the temperature retrieval, including unique on-orbit operations that allow for a better understanding of the instrument response. The MIGHTI measurement approach for temperatures is distinguished by concurrent observations from two different sensors, allowing for two self-consistent temperature products. We compare the MIGHTI temperatures against existing MLT space-borne and ground-based observations. The MIGHTI temperatures are within 7 K of these observations on average from 90–95 km throughout the day and night. In the daytime on average from 99–105 km, MIGHTI temperatures are higher than coincident observations by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on NASA’s TIMED satellite by 18 K. Because the difference between the MIGHTI and SABER observations is predominantly a constant bias at a given altitude, conclusions of scientific analyses that are based on temperature variations are largely unaffected.
A Review of Sampling Exploration and Devices for Extraterrestrial Celestial BodiesZhang, Xu; Zhang, Guoqing; Xie, Heping; Gao, Mingzhong; Wen, Yufeng
doi: 10.1007/s11214-022-00926-ypmid: N/A
Sampling soil or rocks from extraterrestrial celestial bodies is the essential step to detecting the existence of water and life in celestial bodies, it is also an important channel to obtain scientific information about the evolution of the solar system and the origin of the universe. To date, a large number of sampling devices have been designed and developed for sampling exploration of extraterrestrial celestial bodies. However, the sampling devices are versatile, and the employed working principle and sampling methods vary in different exploration missions and celestial bodies’ environments. The present work focuses on the exploration history, celestial bodies’ environment, and sampling devices of extraterrestrial celestial bodies (mainly the Moon, Mars, and small celestial bodies), and provides a systematic review. First, the exploration history and future exploration plans of extraterrestrial celestial bodies are reviewed, which outlines the features of the exploration methods and sampling devices. In the overview of the exploration history, it is found that the failure of sampling exploration is mainly due to the unknown of the celestial bodies’ environment. Therefore, the surface environment and geology of extraterrestrial celestial bodies are further summarized, and whereby the influence of the environment on sampling device design and performance in the exploration process is analyzed. Then a focused analysis of the sampling devices that have been used in previous exploration missions and recent advances has been conducted, which provides a comprehensive description of their exploration goals, operating principles, and properties. This work summarizes the current sampling methods into nine types: excavating, drilling, grinding, grabbing, projecting, penetrating, wire-line coring, ultrasonic-assisted coring, and pneumatic, for which their advantages, disadvantages, and scope of application are analyzed. Finally, the limitations and challenges faced by extraterrestrial bodies’ sampling exploration are discussed, with prospects for future sampling exploration techniques, which can provide a reference for the subsequent in-depth development of extraterrestrial celestial bodies’ sampling devices.
Neutrino-Induced Decay: A Critical Review of the ArgumentsPommé, S.; Pelczar, K.
doi: 10.1007/s11214-022-00932-0pmid: N/A
There has been scientific debate about speculations that ‘neutrino-induced’ radioactive decay causes apparent violations of the exponential-decay law. Sturrock and others repeatedly publish papers asserting influences by solar and cosmic neutrinos on radioactive decay measurements and therefrom draw conclusions about space science that are highly speculative. Recurrent themes in their work are claims that the solar neutrino flux reveals oscillations at a monthly rate which can be linked to solar rotation, that annual and monthly oscillations occur in radioactive decay rates or directionality of emitted radiation which can be linked to variations in solar and cosmic neutrino flux hitting Earth’s surface, and that unstable radioactivity measurements can be used as a source of information about the interior of the Sun and dark matter. Radionuclide metrologists have extensively investigated and refuted their arguments. Metrological evidence shows that radioactive decay does not violate the exponential-decay law and is not a probe for variations in solar neutrino flux. In this review paper, the main arguments of Sturrock are listed and counterarguments are presented. Reference is made to earlier published work in which the evidence has been scrutinised in detail.
Ionospheric Connections (ICON) Ion Velocity Meter (IVM) Observations of the Equatorial Ionosphere at Solar MinimumHeelis, R. A.; Depew, M. D.; Chen, Y.-J.; Perdue, M. D.
doi: 10.1007/s11214-022-00936-wpmid: N/A
The Ionospheric CONnections (ICON) mission has been continuously operating during the period from January 2020 to December 2021 providing simultaneous measurements of the thermal plasma properties near 600 km altitude and the neutral atmosphere and ionosphere in the altitude range 100 km to 500 km at low and middle latitudes. During this period of extremely low to moderately low solar activity, the evolving properties of the topside ionospheric density, composition, temperature and drift velocity at the satellite location are described using measurements from the Ion Velocity Meter (IVM). In the early months of 2020, the very low solar activity and relatively high abundance of H+ in the total plasma density present a challenge to a robust description of the full local time distribution of the topside ion drifts. However, the quality of measurements of the ionospheric composition and temperature are not impacted by low solar activity conditions and changes in the O+ and H+ concentrations and their effects on the energy balance in the topside can be investigated as solar activity changes. As the relative abundance of O+ increases, the susceptibility of the ion drift determination to the local plasma environment around the spacecraft is reduced and a more robust determination of the ion drift at all local times is possible. From October 2020 onward, the relationships between the topside ionospheric dynamics and the ionospheric density and temperature can be investigated and the relationships between the plasma drifts and the underlying neutral wind drivers can be established.
Characterization of the Daytime Ionosphere with ICON EUV Airglow Limb ProfilesStephan, Andrew W.; Sirk, Martin M.; Korpela, Eric J.; England, Scott L.; Immel, Thomas J.
doi: 10.1007/s11214-022-00933-zpmid: N/A
The NASA Ionospheric Connection Explorer Extreme Ultraviolet spectrograph, ICON EUV, images one-dimensional altitude profiles of the daytime extreme-ultraviolet (EUV) airglow between 54-88 nm. This spectral range contains several OII emission features derived from the photoionization of atomic oxygen by solar EUV. The primary target of the ICON EUV is the bright OII (4P – 4S) triplet emission spanning 83.2-83.4 nm that is used in combination with a dimmer but complementary feature (2P – 2D) spanning 61.6-61.7 nm that are jointly analyzed with an algorithm that uses discrete inverse theory to optimize a forward model of these emissions to infer the best-fit solution of ionospheric O+ density profile between 150-450 km. From this result, the daytime ionospheric F-region peak electron density and height, NmF2 and hmF2 respectively, are inferred. The science goals of ICON require these measurements be made in the regions of interest with a vertical resolution in hmF2 of 20 km and a 20% precision in NmF2 within a 60-second integration corresponding to a 500 km sampling along the orbit track. This paper describes the results from the ICON EUV over the first year of the mission, which occurred primarily under solar minimum conditions. It describes adjustments made to the algorithm to improve not only the quality of data products during this time, but also to improve speed and performance while simultaneously meeting the ICON measurement requirements. It also provides examples of results and an overview of key features and limitations to consider when using these products for scientific studies.
Dust in and Around the Heliosphere and AstrospheresSterken, Veerle J.; Baalmann, Lennart R.; Draine, Bruce T.; Godenko, Egor; Herbst, Konstantin; Hsu, Hsiang-Wen; Hunziker, Silvan; Izmodenov, Vladislav; Lallement, Rosine; Slavin, Jonathan D.
doi: 10.1007/s11214-022-00939-7pmid: 36507309
Interstellar dust particles were discovered in situ, in the solar system, with the Ulysses mission’s dust detector in 1992. Ever since, more interstellar dust particles have been measured inside the solar system by various missions, providing insight into not only the composition of such far-away visitors, but also in their dynamics and interaction with the heliosphere. The dynamics of interstellar (and interplanetary) dust in the solar/stellar systems depend on the dust properties and also on the space environment, in particular on the heliospheric/astrospheric plasma, and the embedded time-variable magnetic fields, via Lorentz forces. Also, solar radiation pressure filters out dust particles depending on their composition. Charge exchanges between the dust and the ambient plasma occur, and pick-up ions can be created. The role of the dust for the physics of the heliosphere and astrospheres is fairly unexplored, but an important and a rapidly growing topic of investigation. This review paper gives an overview of dust processes in heliospheric and astrospheric environments, with its resulting dynamics and consequences. It discusses theoretical modeling, and reviews in situ measurements and remote sensing of dust in and near our heliosphere and astrospheres, with the latter being a newly emerging field of science. Finally, it summarizes the open questions in the field.
Meso-Scale Electrodynamic Coupling of the Earth Magnetosphere-Ionosphere SystemYu, Yiqun; Cao, Jinbin; Pu, Zuyin; Jordanova, Vania K.; Ridley, Aaron
doi: 10.1007/s11214-022-00940-0pmid: N/A
Within the fully integrated magnetosphere-ionosphere system, many electrodynamic processes interact with each other. We review recent advances in understanding three major meso-scale coupling processes within the system: the transient field-aligned currents (FACs), mid-latitude plasma convection, and auroral particle precipitation. (1) Transient FACs arise due to disturbances from either dayside or nightside magnetosphere. As the interplanetary shocks suddenly compress the dayside magnetosphere, short-lived FACs are induced at high latitudes with their polarity successively changing. Magnetotail dynamics, such as substorm injections, can also disturb the current structures, leading to the formation of substorm current wedges and ring current disruption. (2) The mid-latitude plasma convection is closely associated with electric fields in the system. Recent studies have unraveled some important features and mechanisms of subauroral fast flows. (3) Charged particles, while drifting around the Earth, often experience precipitating loss down to the upper atmosphere, enhancing the auroral conductivity. Recent studies have been devoted to developing more self-consistent geospace circulation models by including a better representation of the auroral conductance. It is expected that including these new advances in geospace circulation models could promisingly strengthen their forecasting capability in space weather applications. The remaining challenges especially in the global modeling of the circulation system are also discussed.