Solar Photon Flux Research Articles

Prospects on the detection of solar dark photons by the International Axion Observatory

Dark (hidden) photons are widely recognised as well motivated candidates for physics beyond the standard model, and have been invoked for the solution of several outstanding problems, including to account for the dark matter in the universe. In this paper, we consider a simple model for dark photons, which is coupled to ordinary matter only through kinetic mixing with ordinary photons. Within this framework, we calculate the flux of solar dark photons on Earth and revise the potential to detect it with the next generation of axion helioscopes, particularly with the International AXion Observatory (IAXO). This paper extends on previous theoretical analyses in two main ways. Firstly, it includes a more complete analysis of the possible sources of dark photons from the sun, including the contribution of the solar magnetic field and of nuclear processes, and secondly it includes predictions on the parameter space accessible in the gas-filled phase of IAXO.

Experimental study on the radiation-induced destruction of organic compounds on the surface of the Moon

Volatile organic molecules and a complex organic refractory material were detected on the Moon and on lunar samples. The Moon’s surface is exposed to a continuous flux of solar UV photons and fast ions, e.g. galactic cosmic rays (GCRs), solar wind (SW), and solar energetic particles (SEPs), that modify the physical and chemical properties of surface materials, thus challenging the survival of organic compounds. With this in mind, the aim of this work is to estimate the lifetime of organic compounds on the Moon’s surface under processing by energetic particles. We performed laboratory experiments to measure the destruction cross section of selected organic compounds, namely methane (CH4), formamide (NH2CHO), and an organic refractory residue, under simulated Moon conditions. Volatile species were deposited at low temperature (17 - 18 K) and irradiated with energetic ions (200 keV) in an ultra-high vacuum chamber. The organic refractory residue was produced after warming up of a CO:CH4 ice mixture irradiated with 200 keV H+ at 18 K. All the samples were analyzed in situ by infrared transmission spectroscopy. We found that destruction cross sections are strongly affected (up to one order of magnitude) by the dilution of a given organic in an inert matrix. Among the selected samples, organic refractory residues are the most resistant to radiation. We estimated the lifetime of organic compounds on the surface of the Moon by calculating the dose rate due to GCRs and SEPs at the Moon’s orbit and by using the experimental cross section values. Taking into account impact gardening, we also estimated the fraction of surviving organic material as a function of depth. Our results are compatible with the detection of CH4 in the LCROSS eject plume originating from layers deeper than about 0.7 m at the Moon’s South Pole and with the identification of complex organic material in lunar samples collected by Apollo 17 mission.

Atmospheric dependence of the direct, diffuse, and global clear-sky conversion ratios between solar photosynthetic active irradiance and photon flux

The ratio of the global solar photosynthetic active radiation (PAR) photon flux (in μmol/m2s) to global solar PAR irradiance (in W/m2) is of interest to convert one into another. This ratio is usually considered as a constant value close to its extraterrestrial value, 4.55μmol/J. However, this ratio depends on the spectral composition of solar radiation at ground level and it is different for the diffuse and beam components of solar irradiance. Under clear-sky conditions, the three PAR ratios (global, beam and diffuse) are determined by the local atmospheric composition and the relative air mass. In this work, the SMARTS spectral irradiance model with MERRA-2 atmospheric inputs is used to evaluate the dependence of these ratios under clear-sky conditions with air mass, aerosol optical depth (AOD), precipitable water vapor and ozone column. The accuracy of the SMARTS beam spectral irradiance is previously assessed using local spectroradiometer measurements. The clear-sky ratios for the diffuse and direct components increase with increasing air mass, while the global ratio shows only a weak air mass dependence. The clear-sky ratios can be modeled with simple bi-variate linear models in air mass and AOD. These results can be used in similar climatic regions to convert PAR flux to PAR irradiance and vice versa with increased accuracy for the global, direct, and diffuse radiation under cloud-free conditions.

Revisiting empirical solar energetic particle scaling relations

Aims. The possible influence of solar superflares on the near-Earth space radiation environment are assessed through the investigation of scaling laws between the peak proton flux and fluence of solar energetic particle (SEP) events with the solar flare soft X-ray peak photon flux. Methods. We compiled a catalog of 65 well-connected (W20-90) SEP events during the last three solar cycles covering a period of ∼34 yr (1984–2020) that were associated with flares of class ≥C6.0, and investigated the statistical relations between the recorded peak proton fluxes (IP) and the fluences (FP) at a set of integral energies from E > 10, > 30, and > 60 to > 100 MeV versus the associated solar flare peak soft X-ray flux in the 1–8 Å band (FSXR). Based on the inferred relations, we calculated the integrated energy dependence of the peak proton flux (IP) and fluence (FP) of the SEP events, assuming that they follow an inverse power law with respect to energy. Finally, we made use of simple physical assumptions, combining our derived scaling laws, and estimated the upper limits for IP and FP focusing on the flare associated with the strongest ground level enhancement (GLE) directly observed to date (GLE 05 on 23 February 1956), and that inferred for the cosmogenic radionuclide-based SEP event of AD774/775. Results. A scaling law relating IP and FP to the solar soft X-ray peak intensity (FSXR) as ∝ $ {F}_{\mathrm{SXR}}^{5/6} $ for a flare with a FSXR = X600 (in the revised scale) is consistent with values of FP inferred for the cosmogenic nuclide event of AD774/775.

Photolysis of Gas-Phase Atmospherically Relevant Monoterpene-Derived Organic Nitrates.

Organic nitrates (ONs) can impact spatial distribution of reactive nitrogen species and ozone formation in the atmosphere. While photolysis of ONs is known to result in the release of NO2 back to the atmosphere, the photolysis rate constants and mechanisms of monoterpene-derived ONs (MT-ONs) have not been well constrained. We investigated the gas-phase photolysis of three synthetic ONs derived from α-pinene, β-pinene, and d-limonene through chamber experiments. The measured photolysis rate constants ranged from (0.55 ± 0.10) × 10-5 to (2.3 ± 0.80) × 10-5 s-1 under chamber black lights. When extrapolated to solar spectral photon flux at a solar zenith angle of 28.14° in summer, the photolysis rate constants were in the range of (4.1 ± 1.4) × 10-5 to (14 ± 6.7) × 10-5 s-1 (corresponding to lifetimes of 2.0 ± 0.96 to 6.8 ± 2.4 h) and (1.7 ± 0.60) × 10-5 to (8.3 ± 4.0) ×10-5 s-1 (3.3 ± 1.6 to 17 ± 6.0 h lifetimes) by using wavelength-dependent and average quantum yields, respectively. Photolysis mechanisms were proposed based on major products detected during photolysis. A zero-dimensional box model was further employed to simulate the photolysis of α-pinene-derived ON under ambient conditions. We found that more than 99% of α-pinene-derived ON can be converted to inorganic nitrogen within 12 h of irradiation and ozone was formed correspondingly. Together, these findings show that photolysis is an important atmospheric sink for MT-ONs and highlight their role in NOx recycling and ozone chemistry.

Ultra‐low Frequency Foreshock Waves and Ion Dynamics at Mars

AbstractWe study the solar wind interaction with Mars in a global three‐dimensional hybrid model. A well‐developed, vast ion foreshock forms under a strongly flow‐aligned interplanetary magnetic field (IMF) configuration but otherwise nominal solar wind and solar minimum photon flux conditions. Large‐scale ultra‐low frequency (ULF) waves are excited in the foreshock by backstreaming ions. The foreshock ULF waves constitute two distinct regions in the analyzed solar wind and IMF situation: the near region where the wave period is 71–83 s and the far region where the wave period is 25–28 s. The near foreshock region waves transmit downstream through the bow shock and affect dynamics of the solar wind and planetary ion populations. Especially, ion precipitation rate into the exobase and planetary ion escape rates fluctuate at the ULF wave period corresponding to the near foreshock region. The peak‐to‐peak amplitude of the modulation is few percent or less. Interestingly, ionospheric oxygen ion escape fluxes show more than two orders of magnitude local modulations in the heavy plume at the same period. Finally, the escape rates of the ionospheric oxygen ion populations are enhanced by 60–70% under flow‐aligned IMF compared to nominal upstream conditions.

Forecasting solar photosynthetic photon flux density under cloud cover effects: novel predictive model using convolutional neural network integrated with long short-term memory network

Forecast models of solar radiation incorporating cloud effects are useful tools to evaluate the impact of stochastic behaviour of cloud movement, real-time integration of photovoltaic energy in power grids, skin cancer and eye disease risk minimisation through solar ultraviolet (UV) index prediction and bio-photosynthetic processes through the modelling of solar photosynthetic photon flux density (PPFD). This research has developed deep learning hybrid model (i.e., CNN-LSTM) to factor in role of cloud effects integrating the merits of convolutional neural networks with long short-term memory networks to forecast near real-time (i.e., 5-min) PPFD in a sub-tropical region Queensland, Australia. The prescribed CLSTM model is trained with real-time sky images that depict stochastic cloud movements captured through a total sky imager (TSI-440) utilising advanced sky image segmentation to reveal cloud chromatic features into their statistical values, and to purposely factor in the cloud variation to optimise the CLSTM model. The model, with its competing algorithms (i.e., CNN, LSTM, deep neural network, extreme learning machine and multivariate adaptive regression spline), are trained with 17 distinct cloud cover inputs considering the chromaticity of red, blue, thin, and opaque cloud statistics, supplemented by solar zenith angle (SZA) to predict short-term PPFD. The models developed with cloud inputs yield accurate results, outperforming the SZA-based models while the best testing performance is recorded by the objective method (i.e., CLSTM) tested over a 7-day measurement period. Specifically, CLSTM yields a testing performance with correlation coefficient r = 0.92, root mean square error RMSE = 210.31 μ mol of photons m−2 s−1, mean absolute error MAE = 150.24 μ mol of photons m−2 s−1, including a relative error of RRMSE = 24.92% MAPE = 38.01%, and Nash Sutcliffe’s coefficient ENS = 0.85, and Legate and McCabe’s Index LM = 0.68 using cloud cover in addition to the SZA as an input. The study shows the importance of cloud inclusion in forecasting solar radiation and evaluating the risk with practical implications in monitoring solar energy, greenhouses and high-value agricultural operations affected by stochastic behaviour of clouds. Additional methodological refinements such as retraining the CLSTM model for hourly and seasonal time scales may aid in the promotion of agricultural crop farming and environmental risk evaluation applications such as predicting the solar UV index and direct normal solar irradiance for renewable energy monitoring systems.

Constraints imposed by the sparse solar photon flux on upconversion and hot carrier solar cells

Efficiently utilising near-infrared solar radiation remains a challenge in advanced solar energy conversion concepts for photocatalysis and photovoltaics. Here we argue that the particulate nature of the solar photon flux limits the efficiency of schemes that rely on the interaction between optically excited states to exploit low energy photons, such as upconversion and hot carrier systems. The solar photon flux poses stringent constraints on the optical absorption strengths and excited state lifetimes required of such schemes to be efficient. We survey reported device architectures and material properties, and present a quantitative assessment of the extent to which they are limited by the sparse solar photon flux. We illustrate why two photon absorption and other non-linear optical methods are completely unsuitable for augmenting solar energy conversion efficiency, and where existing upconversion and hot carrier solar cell schemes stand against the photon flux criterion. Finally, we describe the opportunities that strategies such as sensitisation and phononic (vibrational) engineering present for bridging the gap between current devices and their efficiency limits.

Synthesis and investigation of a hexyl substituted thieno-fused BODIPY derivative as a versatile near-IR fluorophore.

The synthesis, photophysical and electrochemical properties of hexyl thiophene substituted thieno[b]-fused BODIPY structure are reported within this work. One such derivative, HTFBod, has been studied, which is one of the rare compounds that has a maximum absorbance wavelength greater than 750 nm among fused BODIPY compounds. In addition, it preserves its significant spectral properties such as high molar absorptivity and fluorescence quantum yield. Electrochemical characterizations indicated that the compound could be a successful candidate for an organic solar cell donor compound due to its low band gap, which is known to improve the short-circuit current (Jsc) values. The compound could also harvest the near-IR portion of the solar irradiance where maximum solar photon flux exists. In addition, its low LUMO value of -4.13 eV contributes to its air stability. Hexyl substituents provide greater solubility which is required in solution-processable organic photovoltaics and further bathochromic shift when compared to similar compounds. Next, the synthesis was accomplished in five steps with higher yields compared to similar compounds in the literature. Heavy atom-free singlet oxygen production analysis has also been performed while it has been shown that the compound cannot produce singlet oxygen, while this property could be acquired via halogen substitution.

Observations of sunlit N<sub>2</sub><sup>+</sup> aurora at high altitudes during the RENU2 flight

Abstract. We present measurements of sunlit aurora during the launch of the Rocket Experiment for Neutral Upwelling 2 (RENU2) on the 13 December 2015, 07:34 UTC. The in situ auroral conditions coincide with those of sunlit aurora and were characterised by the 391.4 and 427.8 nm N2+ emissions. A correlation between several auroral wavelengths, as measured by a meridian-scanning photometer, was used to detect sunlit aurora and indirectly neutral upwelling. These results, based on ground data, agree well with the RENU2 measurements recorded during its pass through the sunlit polar cusp. Using in situ data from RENU2 and the solar photon flux, it was estimated that the sunlit aurora was a major part (≈40 %) of the observed 427.8 nm emission.

Viability of Bacillus subtilis Spores Exposed to Ultraviolet Light at Ocean World Surface Temperatures.

This work investigated microorganism survival under temperature and ultraviolet (UV) radiation conditions found at the surface of ice-covered ocean worlds. These studies were motivated by a desire to understand the ability of resilient forms of life to survive under such conditions as a proxy for potential endogenic life and to inform planetary protection protocols for future missions. To accomplish this, we irradiated Bacillus subtilis spores with solar-like UV photons at temperatures ranging from room temperature down to 11 K and reported survival fractions with respect to fluence. We observed an increase in survival at low temperatures and found that the inactivation rate follows an Arrhenius-type behavior above 60 K. For solar-photon fluxes and surface temperatures at Europa and Enceladus, we found that Bacillus subtilis spores would be inactivated in less than an hour when in direct sunlight.

Quanta Photogrammetry of Experimental Geodetic Satellite for remote detection of micrometeoroid and orbital debris impacts

The conventional detection of micrometeoroid and orbital debris (MMOD) impacts on satellites is based on in-situ sensing or direct, visual inspection of the retrieved surface elements exposed to the particle flux and thus requires active in-orbit operations. We propose Quanta Photogrammetry (QPM) as an optical method for remote detection of surface structural anomalies of passive satellites by measuring solar photon flux reflected off the satellite surface towards the ground detection system.The hypertemporal light curves of the Experimental Geodetic Satellite - Ajisai (NORAD 16908, altitude of 1490 km) are collected with the state-of-the-art photon counting system designed and operated by the Graz Satellite Laser Ranging Observatory (Austria). QPM utilizes the inertial attitude model of the satellite to project the high-rate photometric samples onto the spacecraft body-fixed frame. The single-photon light curves collected from Oct. 2015 until Jan. 2018 are used to map reflectivity of 149 mirror panels on-board Ajisai (approx. size of 20 × 20 cm each) and reveal relatively small, irregularly shaped and spot-like anomalies that can indicate surface degradation due to the long-term environmental interactions and MMOD hypervelocity impacts.

Enhanced photocatalytic hydrogen evolution from organic semiconductor heterojunction nanoparticles.

Photocatalysts formed from a single organic semiconductor typically suffer from inefficient intrinsic charge generation, which leads to low photocatalytic activities. We demonstrate that incorporating a heterojunction between a donor polymer (PTB7-Th) and non-fullerene acceptor (EH-IDTBR) in organic nanoparticles (NPs) can result in hydrogen evolution photocatalysts with greatly enhanced photocatalytic activity. Control of the nanomorphology of these NPs was achieved by varying the stabilizing surfactant employed during NP fabrication, converting it from a core-shell structure to an intermixed donor/acceptor blend and increasing H2 evolution by an order of magnitude. The resulting photocatalysts display an unprecedentedly high H2 evolution rate of over 60,000 µmol h-1 g-1 under 350 to 800 nm illumination, and external quantum efficiencies over 6% in the region of maximum solar photon flux.

New electron donor in planar heterojunction: optimization of the cells efficiency through the choice of the hole-extracting layer

Due to their light weight, flexibility and semi-transparency the organic photovoltaic cells play an important role for solar conversion photovoltaic (OPV). To achieve good performances, both donor and acceptor materials in OPVs need to have good extinction coefficients, high stabilities and good film morphologies. Since the donor plays a critical role as the absorber to solar photon flux, donor materials require wide optical absorption to match the solar spectrum. In this work the couple ED/EA in planar heterojunction was Tetracyano 4,4'-bis(9Hcarbazol-9-yl) biphenyl (TCC)/fullerene (C60). Optimum results are obtained when MoO3 alone is used as Hole Transporting Layer (HTL). The J/V characteristics do not exhibit S-shaped curves up to a TCC layer thickness of 15 nm, while they did when the HTL includes CuI. Theoretical study, complementary to the experimental study, shows that in the case of S-shaped curve the cell behaves as if it was made up of 2 diodes, one of which would be opposed to the flow of the photogenerated current. In the case of MoO3 HTL, i.e; without shaped curve, the optimum thickness is 13 nm, giving an efficiency η = 2.30% with V oc = 0.9 V, J sc = 5.17 mA/cm2 and FF = 49%.

UVC photon-induced denaturing of DNA: A possible dissipative route to Archean enzyme-less replication

Non-equilibrium thermodynamics is a relevant framework from within which to address formidable difficulties encountered in explaining the origin of life; from molecular synthesis and complexation, enzyme-less proliferation, to evolution (including the acquisition of homochirality and information). From within this framework we have proposed that the origin of life was the origin of the dissipative structuring of organic pigments which became the fundamental molecules of life (e.g. RNA and DNA) proliferated through autocatalytic photochemical reactions under the thermodynamic imperative of dissipating the imposed UVC solar photon flux available at the Archean surface. Here we present experimental evidence demonstrating that the absorption and dissipation of UVC light by synthetic DNA of 25 base pairs (and also natural salmon sperm DNA) over a range of temperatures, including below their melting temperature, leads to denaturing. Since denaturing is a non-trivial step on route to enzyme-less replication, our data suggest the possibility of a dissipative route to DNA replication at the origin of life. Such a dissipation-replication relation provides a simple mechanism for the early accumulation of both homochirality and information. Possible mechanisms of UVC photon-induced denaturing of DNA are discussed.

Application of solar photocatalytic ozonation in water treatment using supported TiO2

TiO2 P25 supported on mullite ceramic foams (CF) and glass raschig rings (GR), have been prepared by dip-coating with calcination at 500 °C. The (photo) catalytic activity of these materials in the degradation of N, N-diethyl-m-toluamide (DEET) by different AOPs, in ultrapure water or in a secondary effluent, has been tested. Under the conditions applied, for a given process, the performance of CF and GR supported catalysts was similar, and a slight improvement was observed only from 1 to 2 TiO2 coatings, indicating that, regardless of the support, after the second coating the amount of TiO2 (2.4 and 0.49 wt% for CF and GR, respectively), was in excess with respect to the solar UV photon flux and/or the ozone entering the reactor. Ozonation was the most effective process for DEET and A254nm removal, whereas solar photocatalytic ozonation led to the highest carboxylates formation and mineralization rates. At pH < 8.5, the presence of 5 mg L−1 PO43- or 20 mg L−1 IC as HCO3-/CO3= had no effect on DOC removal by this system, but some HO· scavenging effect was noticed when 40 mg L−1 IC was present, more markedly at pH > 8.5. The impact of the water matrix (ultrapure water, DOC0 15 mg L−1; or a secondary effluent, DOC0 11 mg L−1 and IC0 20 mg L−1), on the effectiveness of photocatalytic oxidation was high, and low for photocatalytic ozonation (45–50% DOC removed from both matrices after 2 h). After several cycles of use, almost no loss of activity of the supported materials was observed. By comparing the characterization results of fresh/used materials their stability is deduced.

Halide Perovskites for Selective Ultraviolet-Harvesting Transparent Photovoltaics

Summary Halide perovskite materials have emerged as a potential Si replacement with excellent photovoltaic properties. There has been growing interest in applying halide perovskites to semitransparent and spatially segmented transparent photovoltaics (TPVs) to enable a greater range of deployment routes. However, the continuous-band absorption of these semiconductors prevents near-infrared selective harvesting typically targeted for TPVs with the highest efficiency and transparency needed to meet the aesthetic demands of many potential applications. In this work, we demonstrate TPVs based on perovskite semiconductors where the band gap is sensitively tuned with a range of compositions to selectively harvest only ultraviolet photons with band gaps between 410 and 440 nm. This approach offers theoretical efficiencies up to 7% with >99% visible transparency when precisely targeting band gaps around 435 nm. Practical optimization of these perovskite cells could quickly yield TPVs with power conversion efficiencies rivaling state-of-the-art near-infrared harvesting TPVs today while also providing a route to higher-efficiency multi-junction TPVs.

The Instruments and Capabilities of the Miniature X-Ray Solar Spectrometer (MinXSS) CubeSats

The Miniature X-ray Solar Spectrometer (MinXSS) CubeSat is the first solar science oriented CubeSat mission flown for the NASA Science Mission Directorate, with the main objective of measuring the solar soft X-ray (SXR) flux and a science goal of determining its influence on Earth’s ionosphere and thermosphere. These observations can also be used to investigate solar quiescent, active region, and flare properties. The MinXSS X-ray instruments consist of a spectrometer, called X123, with a nominal 0.15 keV full-width at half-maximum (FWHM) resolution at 5.9 keV and a broadband X-ray photometer, called XP. Both instruments are designed to obtain measurements from 0.5 – 30 keV at a nominal time cadence of 10 s. A description of the MinXSS instruments, performance capabilities, and relation to the Geostationary Operational Environmental Satellite (GOES) 0.1 – 0.8 nm flux is given in this article. Early MinXSS results demonstrate the capability of measuring variations of the solar spectral soft X-ray (SXR) flux between 0.8 – 12 keV from at least GOES A5–M5 (5 times 10^{-8},mbox{--},5 times10^{-5}~mbox{W},mbox{m}^{-2}) levels and of inferring physical properties (temperature and emission measure) from the MinXSS data alone. Moreover, coronal elemental abundances can be inferred, specifically for Fe, Ca, Si, Mg, S, Ar, and Ni, when the count rate is sufficiently high at each elemental spectral feature. Additionally, temperature response curves and emission measure loci demonstrate the MinXSS sensitivity to plasma emission at different temperatures. MinXSS observations coupled with those from other solar observatories can help address some of the most compelling questions in solar coronal physics. Finally, simultaneous observations by MinXSS and the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) can provide the most spectrally complete soft X-ray solar flare photon flux measurements to date.

Modelling ROS formation in boreal lakes from interactions between dissolved organic matter and absorbed solar photon flux

Concentrations of dissolved organic matter (DOM) are increasing in a large number of lakes across the Northern hemisphere. This browning serves a dual role for biota by protecting against harmful ultraviolet radiation, while also absorbing photosynthetically active radiation. The photochemical activation of DOM and subsequent formation of reactive oxygen species (ROS) is a potentially harmful side effect, but can be difficult to measure directly in situ. In this study, we combine a data set of physico-chemical properties from 71 Nordic lakes with in vitro ROS formation quantum yields to predict ROS formations across a representative boreal ecosystem gradient. For the upper centimeter of the water column, we calculate ROS formations in the range of 7.93–12.56 μmol L−1 h−1. In the first meter, they range between 1.69 and 6.69 μmol L−1 h−1 and in the remaining depth the range is 0.01–0.46 μmol L−1 h−1. These ROS formations are comparable with previously field-measured hydrogen peroxide formation rates and likely affect both phyto- and zooplankton, as well as lake chemistry. Interestingly, wavelengths of the visible spectrum (>400 nm) contribute more than half of the overall ROS formation in surface-near water layers. The association between DOM and ROS formation was found to be two-fold. While DOM promotes ROS formation in the first centimeters of the water column, the shading effect of light attenuation overpowers this with increasing depth. In the context of water browning, our results indicate the emergence of an underestimated oxidative stress environment for lake biota in the upper centimeters of the water column.

Locations Where Space Weather Energy Impacts the Atmosphere

In this review we consider aspects of space weather that can have a severe impact on the terrestrial atmosphere. We begin by identifying the pre-conditioning role of the Sun on the temperature and density of the upper atmosphere. This effect we define as “space climatology”. Space weather effects are then defined as severe departures from this state of the atmospheric energy and density. Three specific forms of space weather are reviewed and we show that each generates severe space weather impacts. The three forms of space weather being considered are the solar photon flux (flares), particle precipitation (aurora), and electromagnetic Joule heating (magnetosphere–ionospheric (M-I) coupling). We provide an overview of the physical processes associated with each of these space weather forms. In each case a very specific altitude range exists over which the processes can most effectively impact the atmosphere. Our argument is that a severe change in the local atmosphere’s state leads to atmospheric heating and other dynamic changes at locations beyond the input heat source region. All three space weather forms have their greatest atmospheric impact between 100 and 130 km. This altitude region comprises the transition between the atmosphere’s mesosphere and thermosphere and is the ionosphere’s E-region. This region is commonly referred to as the Space Atmosphere Interaction Region (SAIR). The SAIR also acts to insulate the lower atmosphere from the space weather impact of energy deposition. A similar space weather zone would be present in atmospheres of other planets and exoplanets.