JGR:Space physics

Syndicate content Wiley: Journal of Geophysical Research: Space Physics: Table of Contents
Table of Contents for Journal of Geophysical Research: Space Physics. List of articles from both the latest and EarlyView issues.
Updated: 1 day 17 hours ago

Responses of Ionospheric Radial Currents to Subauroral Polarization Streams During Quiet Periods

Mon, 01/01/2024 - 10:24
Abstract

Using 4 years of ionospheric radial current (IRC) from Swarm and ion velocity from the Defense Meteorological Satellite Program, our work investigates the response of IRC to the subauroral polarization streams (SAPS) during the quiet time for the first time. Both noontime (magnetic local time, MLT 11–14) inward and duskside (MLT 18–19) outward IRC get strengthened in amplitude. The noontime inward ΔIRC is attributed to the penetration westward electric field at low-mid latitudes. It drives the poleward Hall currents and equatorward polarization electric field, which maps to the dip equator to form an inward ΔIRC at F layer. At dusk, the SAPS-poleward electric field could directly penetrate to the low-mid latitudes, mapping to the dip equator to drive the outward ΔIRC. The substorms-associated westward electric field is also critical in modulation of ΔIRC, resulting in a larger inward (weaker outward) ΔIRC under high auroral electrojet (AE) index than that under low AE around noon (dusk).

Resolving Some Longstanding Issues in Far Ultraviolet Remote Sensing: A Self‐Consistent Analysis of the GUVI and SEE Observations on the TIMED Mission

Fri, 12/29/2023 - 22:29
Abstract

Far Ultraviolet (FUV) remote sensing has been used in aeronomy missions as a powerful means to measure the temperature and compositions in the upper atmospheres of terrestrial planets. However, despite decades of continual development, outstanding challenges remain in this field. Particularly, there is currently a lack of methods for the examination and improvement of the data products in FUV remote sensing. As a result, longstanding issues exist in many of those data products. Here we demonstrate that a self-consistent analysis of multi-band airglow observations in the spectral range of ∼120–180 nm can serve as a useful means for examination and improvement of the data products in FUV remote sensing. The Global Ultraviolet Imager (GUVI) and Solar EUV Experiment (SEE) observations on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics mission are used for the demonstration. Through a self-consistent analysis, we reconcile the thermospheric column O/N2 density ratios that are retrieved respectively from the GUVI limb and disk scans, by numerically correcting a systematic offset between those observations. We also reconcile the models with the observed 121.6 and 130.4 nm emission that have shown large discrepancies in the literature. The self-consistent analysis indicates that the SEE measurements of the solar spectral irradiance below ∼45 nm need to be scaled down by ∼25%, whereas the SEE measurements of the solar 121.6 and 130.4 nm fluxes are highly accurate, with errors less than ∼3%. Our results achieve unprecedented agreement (better than ∼5%) between models and observations and provide a novel method for data examination and improvement in FUV remote sensing.

Statistical Analysis of Electric Currents Within the Magnetosheath Using Dayside Magnetospheric Multiscale Mission Observations

Fri, 12/29/2023 - 22:28
Abstract

Earth's magnetosheath is the region of shocked plasma that mediates coupling between the solar wind and magnetosphere. Magnetohydrodynamic (MHD) simulations predict electric current closure across the magnetosheath from the bow shock to the magnetopause. These currents provide a J × B force that diverts plasma flow along the flanks of the magnetosphere. Observations by the NASA Magnetospheric Multiscale (MMS) mission show that within the magnetosheath there are large amplitude, localized currents during periods of intense turbulence. We perform a statistical analysis of magnetic field data from the first 6 years (2015–2021) of the MMS mission during intervals when the satellites are on the dayside and generate statistical maps of electric current derived using the curlometer technique. We find that during the low magnetosonic Mach number regime (M MS < 5), the predicted current closure pattern becomes apparent for northward and southward IMF orientations, but not dawnward or duskward. For M MS > 5, results suggest that for all IMF orientations this large-scale current closure pattern is not apparent, even after separating out quasi-perpendicular (θ bn ≥ 45°) and quasi-parallel (θ bn < 45°) bow shock conditions. Instead, the magnetosheath is dominated by small-scale filamented current sheets that may be attributed to magnetosheath turbulence.

On the Energy Coupling From Magnetosonic Waves to High‐Frequency Electromagnetic Ion Cyclotron Waves: Statistical Analysis

Thu, 12/28/2023 - 22:53
Abstract

In the inner magnetosphere, fast magnetosonic waves (MS waves) are known to resonantly interact with ring current protons, causing these protons to gain energy preferentially in the direction perpendicular to the background magnetic field. An anisotropic distribution of enhanced ring current protons is a necessary condition to excite electromagnetic ion cyclotron (EMIC) waves which are known to facilitate a rapid depletion of ultra-relativistic electrons in the outer radiation belt. So, when a simultaneous observation of high-frequency EMIC (HFEMIC) waves, anisotropic low-energy protons, and MS waves was first reported, a chain of energy flow from MS waves to HFEMIC waves through proton heating was naturally proposed. In this study, we carry out a statistical analysis using Van Allen Probes data to provide deeper insights into this energy pathway. Our results show that the occurrence of HFEMIC waves exhibits good correlation with the enhanced flux and anisotropy of low-energy protons, but the correlation between the low-energy protons and the concurrent MS waves is rather poor. The latter result is given support by quasilinear diffusion analysis, indicating negligible momentum diffusion rates at sub-keV energies, unless MS wave frequency gets very close to the proton cyclotron frequency (which constitutes only a small number of the cases). The fact that the first chain of the coupling is statistically inconclusive calls for an alternative explanation for the major source of the low-energy anisotropic proton population in the inner magnetosphere.

Investigation of Different ΣO/N2 Variations Observed by GOLD During a Minor Geomagnetic Storm From 2 to 4 August 2021

Thu, 12/28/2023 - 22:53
Abstract

During a minor geomagnetic storm occurring from Aug 2 (day-of-year (DOY) 214) to Aug 4 (DOY 216), 2021, the National Aeronautics and Space Administration Global-scale Observations of the Limb and Disk (GOLD) mission observed different column density ratio of O to N2 (ΣO/N2) variations in storm main and recovery phases. The percentage difference of ΣO/N2 between DOY 215 (disturbed day, main phase) and DOY 213 (quiet reference day) exhibits a depletion on the east side of the GOLD field-of-view (FOV). However, that of ΣO/N2 between DOY 216 (recovery phase) and 213 shows depletions on the west side of GOLD FOV. The National Center for Atmospheric Research Thermosphere Ionosphere Electrodynamics General Circulation Model qualitatively reproduced the observations. Analysis of the model output illustrates that the ΣO/N2 patterns in the two days are both formed due to the classical thermospheric composition theory and formed on DOY 214 and 215, respectively. Further investigation found that the ΣO/N2 depletion on DOY 214 and 215 both initially formed near 120–180°E, but the one on DOY 215 then quickly moved westward into the GOLD FOV, from local post-midnight to pre-midnight, near 19 UT. Then it moves equatorward and slowly westward. This results in the observed depletion structure on the west side of GOLD FOV. Model simulations show that the quick westward movement near 19 UT is due to the dominant positive Interplanetary Magnetic Field east-west component (By) conditions.

Ionospheric Response to Solar EUV Radiation Variations Using GOLD Observations and the CTIPe Model

Wed, 12/27/2023 - 22:34
Abstract

To understand the global response of thermospheric-ionospheric (TI) parameters to variations in solar irradiance measurements from the Global-Scale Observations of the Limb and Disk (GOLD) ultraviolet imaging spectrograph, solar radio flux F10.7, predictions from the Coupled Thermosphere Ionosphere Plasmasphere electrodynamics (CTIPe) model, and International Global Navigation Satellite System Service total electron content maps (TEC) have been used. Various parameters such as GOLD O/N 2, O 2, and the nighttime peak electron density (Nmax) have been compared with the CTIPe model simulations. The GOLD observed Nmax shows a number of significant features including a winter anomaly and an equatorial ionization anomaly. The comparison with solar proxies showed that the GOLD Q EUV correlates very well with the EUV observations compared to the F10.7 index. The study also examined the relationship between the solar proxies and Nmax on different time scales and found that Nmax responded significantly to Q EUV at both medium- and long-term timescales. Furthermore, a low correlation between Nmax in the equatorial region and solar proxies was found. A delayed ionospheric TEC response against solar flux variations within the 27-day solar rotation was investigated. This ionospheric delay of TEC with respect to solar flux was observed to be less than 1 day, which was reproduced in model simulations. The current study has shown that the GOLD observations can be used to investigate the delayed ionospheric response and to gain a better understanding of the influence of solar activity on the TI system.

The Hemispheric Difference in Electric Potential and Electron Precipitation Observed by DMSP in the Auroral Zone

Wed, 12/27/2023 - 22:29
Abstract

In this case study, we focus on how hemispheric differences in the electric potential distribution in the auroral zones are related to hemispheric differences in the energetic particle precipitation that indicate the presence of field-aligned potential drops. Utilizing data during the spring and fall equinox in 2013 and 2014 from the Defense Meteorological Satellite Program (DMSP) F16 and F17 satellites, we systematically examine simultaneous measurements of plasma drift velocity and particle precipitation in magnetically conjugate regions across the auroral zone in both hemispheres. This allows us to establish the degree to which the interhemispheric differences in ionospheric electric potential may be accounted for by field-aligned potential drops. Thirty-seven eligible cases examined show accelerated electron energy spectra at conjugate locations in the northern and/or southern hemispheres. Of these 37 cases, 23 show conjugate differences in electric potential that agree qualitatively with the observed electron acceleration and average energy of precipitating electrons in each hemisphere. This result suggests that the hemispheric differences in ionospheric electric potential in the auroral zone may be most frequently accounted for by field-aligned potential drops along the magnetic flux tubes connecting conjugate points to the equatorial plane. The spatial and temporal variability of the potential distribution, electron precipitation, and magnetic field configuration could account for deviations from the normally observed situation in the remaining cases. More magnetically conjugate observations at various altitudes in both hemispheres are needed to investigate this hemispheric coupling in more detail.

Fast Spacecraft Charging Mitigation With Plasma Contactors During High‐Power Electron Beam Emission in the GEO Environment

Wed, 12/27/2023 - 22:23
Abstract

The emission of artificial electron beams causes an active spacecraft charging effect that poses challenges for electron beam sounding experiments. Plasma contactors have been suggested as a potential solution to this issue based on theoretical and simulation studies, but the impact of these contactors on spacecraft potentials in complex space environments remains unexplored. This paper investigates the fast active charging effect of spacecraft under the action of plasma contactors in the geostationary Earth orbit environment by using a two-dimensional Particle-in-Cell model. We analyze and compare the effects of the “ion emission” process of the plasma contactor and the “electron collection” process of the background plasma on the spacecraft potential at different beam and environment parameters, as well as the coupling effects when both processes occur simultaneously. Our findings indicate that the “ion emission” and “electron collection” processes are the primary factors in determining the spacecraft potential in relatively thin and dense plasma environments, respectively. When the two processes occur together, the contactor plasma cloud increases the “electron collection” return current by expanding the range of the positive potential area around the spacecraft, while the dense background plasma mediates and provides the return current to ensure that the plasma contactor can effectively suppress the active charging effect even after the ion sheath is present. These results suggest that a reasonable adjustment of the contactor parameters based on the relationship between the electron beam and the background environment can effectively extend the normal emission time of the electron beam.

Investigation of the Occurrence Characteristics and Possible Origins of Daytime Spread F Irregularities in Low Latitude Region

Tue, 12/26/2023 - 22:44
Abstract

A study of occurrence characteristics and morphology of daytime spread F (DSF) irregularities was conducted using ionosonde from 2013 to 2020 over low-latitude Puer station in the China sector. In this study, a day with two or more consecutive F-region diffuse echo ionograms within one hour from local sunrise to sunset at an altitude of 250 km is considered a DSF day. The results show that the DSF irregularities observed in different solar activity years have a similar seasonal distribution, manifesting as frequent occurrences in June solstice with a maximum occurrence near sunrise. Furthermore, the morphology of most DSFs on the ionograms is predominantly frequency spread F, with a few observed near sunrise as MSF and RSF. In contrast to in high solar activity years (HSAY, 2013–2015), an interesting phenomenon of DSF irregularities in low solar activity years (LSAY, 2016–2020) is presented. That is, in the late afternoon hours (15–18 LT), DSFs have an unexpectedly high occurrence rate during the December solstice. By analyzing the virtual height variations for iso-frequency plots of the DSF event occurring in the afternoon, these DSF irregularities were found to be likely associated with daytime medium-scale traveling ionospheric disturbances (MSTIDs). Compared with the observed characteristics of the nighttime spread F, the fossils of nighttime plasma bubbles irregularities might play a key role in the development of DSF occurring in the early morning. At the same time, the influence of daytime MSTIDs on DSF irregularities occurring in the late afternoon hours cannot be ignored.

Persistent Pitch Angle Anisotropies of Relativistic Electrons in the Outer Radiation Belts

Tue, 12/26/2023 - 22:44
Abstract

Pitch angle distributions (PADs) in the radiation belts are well characterized with sin n (α). By tracking the exponent “n,” termed pitch angle index, we are able to observe persistent and cross-energy changes in PADs of Van Allen radiation belt electrons using Van Allen Probes particle observations. The PAD measurements are well fit down to a single satellite spin, and therefore can track spatially and temporally confined changes to determine the connection between particles and waves. With this method, we study long-lasting and high-energy anisotropic electron PADs during a quiet period over 2 days, 26 and 27 June 2013. One potential driver for these changes is electromagnetic ion cyclotron wave interaction with the particles. We use several ground magnetometer stations from Canadian Array for Realtime Investigations of Magnetic Activity and Finnish pulsation magnetometer network of Sodankylä Geophysical Observatory to observe waves during the 2 days of interest. The connection between the waves and particles is inconclusive, although there is some temporal overlap of the phenomenon.

Two‐Component Phase Scintillation Spectra in the Auroral Region: Observations and Model

Tue, 12/26/2023 - 22:38
Abstract

The random amplitude and phase fluctuations observed in trans-ionospheric radio signals are caused by the presence of electron density irregularities in the ionosphere. Ground-based measurements of radio wave signals provide information about the medium through which these signals propagate. The Canadian High Arctic Ionospheric Network (CHAIN) Global Position System (GPS) receivers record radio signals emitted by the GPS satellites, enabling the study of their spectral characteristics. This study presents examples of phase spectra with two power-law components. These components exhibit steeper spectral slopes at higher frequencies and shallower ones at lower frequencies. To be more specific, we conducted a spectral characterization of sixty one (61) events recorded by the CHAIN Churchill GPS receiver, which is located in the auroral oval. When fluctuations above the background level are only observed in the phase, the spectra tend to be systematically steeper. Conversely, the power increase in higher frequency fluctuations accompanying amplitude scintillation tends to result in shallower spectra. A basic yet powerful model of radio wave propagation through a turbulent ionosphere, characterized by a power law electron density spectrum, can help to explain the two power laws observed in the scintillation events presented in this study by identifying the role played by small-scale ionospheric irregularities in diffraction.

New Chorus Diffusion Coefficients for Radiation Belt Modeling

Tue, 12/26/2023 - 22:34
Abstract

Whistler mode chorus is an important magnetospheric wave emission playing a major role in radiation belt dynamics, where it contributes to both the acceleration and loss of relativistic electrons. In this study we compute bounce and drift averaged chorus diffusion coefficients for 3.0 < L* < 6.0, using the TS04 external magnetic field model, taking into account co-located near-equatorial measurements of the wave intensity and f pe /f ce , by combining the Van Allen probes measurements with data from a multi-satellite VLF wave database. The variation of chorus wave normal angle (WNA) with spatial location and f pe /f ce is also taken into account. We find that chorus propagating at small WNAs has the dominant contribution to the diffusion rates in most MLT sectors. However, in the region 4 ≤ MLT < 11 high WNAs dominate at intermediate pitch angles. In the region 3 < L* < 4, the bounce and drift averaged pitch angle and energy diffusion rates during active conditions are primarily larger than those in our earlier models by up to a factor of 10 depending on energy and pitch angle. Further out, the results are similar. We find that the bounce and drift averaged energy and pitch angle diffusion rates can be significantly larger than the new model in regions of low fpe/fceeq ${f}_{pe}/{f}_{ce}^{eq}$, where the differences can be up to a factor of 10 depending on energy and pitch angle.

Extreme Geomagnetic Disturbances (GMDs) Observed in Eastern Arctic Canada: Occurrence Characteristics and Solar Cycle Dependence

Tue, 12/26/2023 - 22:28
Abstract

Extreme (>20 nT/s) geomagnetic disturbances (GMDs, also denoted as MPEs—magnetic perturbation events)—impulsive nighttime disturbances with time scale ∼5–10 min, have sufficient amplitude to cause bursts of geomagnetically induced currents (GICs) that can damage technical infrastructure. In this study, we present occurrence statistics for extreme GMD events from five stations in the MACCS and AUTUMNX magnetometer arrays in Arctic Canada at magnetic latitudes ranging from 65° to 75°. We report all large (≥6 nT/s) and extreme GMDs from these stations from 2011 through 2022 to analyze variations of GMD activity over a full solar cycle and compare them to those found in three earlier studies. GMD activity between 2011 and 2022 did not closely follow the sunspot cycle, but instead was lowest during its rising phase and maximum (2011–2014) and highest during the early declining phase (2015–2017). Most of these GMDs, especially the most extreme, were associated with high-speed solar wind streams (Vsw >600 km/s) and steady solar wind pressure. All extreme GMDs occurred within 80 min after substorm onsets, but few within 5 min. Multistation data often revealed a poleward progression of GMDs, consistent with a tailward retreat of the magnetotail reconnection region. These observations indicate that extreme GIC hazard conditions can occur for a variety of solar wind drivers and geomagnetic conditions, not only for fast-coronal mass ejection driven storms.

Kinetic Modeling of Ionospheric Outflows in Pressure Cooker Environments

Tue, 12/26/2023 - 22:24
Abstract

Plasma escape from the high-latitude ionosphere (ion outflow) serves as a significant source of heavy plasma to the magnetospheric plasma sheet and ring current regions. Outflows alter mass density and reconnection rates, hence global responses of the magnetosphere. A new fully kinetic and semi-kinetic model, KAOS (Kinetic model of Auroral ion OutflowS), is constructed from first principles which traces large numbers of individual O+ ion macro-particles along curved magnetic field lines, using a guiding-center approximation, in order to facilitate calculation of ion distribution functions and moments. Particle forces include mirror and parallel electric field forces, a self-consistent ambipolar electric field, and a parameterized source of ion cyclotron resonance wave heating, thought to be central to the transverse energization of ions. The model is initiated with a steady-state ion density altitude profile and Maxwellian velocity distribution and particle trajectories are advanced via a direct simulation Monte Carlo scheme. This outlines the implementation of the kinetic outflow model, demonstrates the model's ability to achieve near-hydrostatic equilibrium necessary for simulation spin-up, and investigates L-shell dependent wave heating and pressure cookers scenarios. This paper illustrates the model initialization process and numerical investigations of L-shell dependent outflows and pressure cooker environments and serves to advance our understanding of the drivers and particle dynamics in the auroral ionosphere.

Stream Interaction Regions in the Minimum of Solar Cycles 23 and 24

Tue, 12/26/2023 - 22:24
Abstract

Stream interaction regions (SIRs) dominate the large-scale solar wind dynamics during the minimum of the solar cycle. The interaction of SIRs with the magnetosphere causes most of geomagnetic storms during this epoch. We used in-situ solar wind observations at 1 AU to study 62 SIRs detected in the interval 2007–2008 (minimum of cycle 23) and 61 SIRs in the interval 2018–2019 (minimum of cycle 24). We compared distinct characteristics of SIRs, such as the solar wind streams velocities, the presence of forward and/or reverse shocks (RS), SIR radial widths, the relative position of the stream interface within the SIRs, SIR latitudinal orientation, and the geoeffectiveness. There were more geomagnetic storms driven by SIRs in cycle 23 than in cycle 24. The pattern of fast solar wind streams in cycle 23 tended to be faster than in cycle 24. We found more SIRs with RS in cycle 23 than in cycle 24. For the geoeffective SIRs, the momentum flows from the fast solar wind to the slow solar wind, as well as their stream interface is closer to the SIR front. Coronal holes associated with SIRs registered in cycle 23 tended to be wider in longitude near the solar equator and/or at midlatitudes. We did not find a clear relation between the geoeffectiveness of the SIRs and their latitudinal inclinations.

Issue Information

Sat, 12/23/2023 - 09:38

No abstract is available for this article.

Energy Transfer Between Various Electron Populations Via Resonant Interaction With Whistler Mode Wave

Thu, 12/21/2023 - 10:23
Abstract

Electron energization in the Earth's radiation belts caused by resonant interaction with whistler mode waves is currently under intense investigation. When the waves are excited due to cyclotron instability in collisionless plasma, that is, when the energy source for the waves is the free energy of unstable electron distribution, particle energization by excited waves is nothing but energy transfer from one group of electrons to another mediated by the waves. An example of such a process is considered in which a quasi-monochromatic whistler mode wave packet with the frequency and the wave normal angle corresponding to the maximum growth rate is excited at the equator. Since the maximum growth rate corresponds to parallel propagating wave, only the first cyclotron resonance particles play a part in this excitation. While propagating from the equator toward the Earth, the wave normal vector becomes more and more oblique, and all cyclotron resonances, in particular, Landau resonance come into play. Wave-particle interaction at Landau resonance leads to the wave damping and the corresponding particle energization on the average. Moreover, we show that the mean square variation of resonant particle energy greatly exceeds the average value, thus, the energy increase of some particles is much larger than the Landau resonance particles get from the wave on the average. This means that the exchange of energy between different groups of particles through a wave is a more efficient process than the amplification or damping of a wave due to its resonant interaction with particles.

Evidence for Electron Precipitation Diffused by Rising‐Tone Quasiperiodic Whistler Waves in Extremely Low L−Shells Observed by CSES

Thu, 12/21/2023 - 10:14
Abstract

Based on the observations by the sun-synchronous circular orbit China Seismo-Electromagnetic Satellite(CSES), a typical case of the rising-tone quasiperiodic (QP) emissions with a large period of around 2 min was reported to appear on the dayside on 23 October 2021. The frequency of QP waves ranges from 2,000 ∼ 3,000 Hz and the wave spectral structure consists of four elements with right-handed polarization. Three elements of them are located at extremely low L-shells from 2 ∼ 3.5. The periodic precipitating fluxes of 100 ∼ 400 keV electrons were found in the conjugate region also observed by CSES, which appeared in the same magnetic field lines with the elements of QP waves, respectively. By numerical simulations of quasi-linear diffusion theory, we confirm that QP emissions can effectively precipitate energetic electrons near the loss cone into the atmosphere in the inner radiation belt. To our best knowledge, this is the first evidence that the rising-tone QP whistler waves scatter electrons in the inner radiation belt. This new finding will help to deepen our understanding of the electron precipitation dynamics in radiation belt physics.

Evidence for Magnetic Reconnection as the Precursor to Discrete Aurora at Mars

Thu, 12/21/2023 - 09:05
Abstract

Discrete aurora at Mars are characterized as localized, short-lasting ultraviolet emissions on the nightside. They are caused by the precipitation of accelerated electron along open magnetic field lines and their collision with the Martian atmosphere. Discrete auroral emissions detected by the Imaging Ultraviolet Spectrograph (IUVS) instrument onboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft occur most frequently over the strongest crustal magnetic anomalies at Mars and under particular local time and upstream interplanetary magnetic field (IMF) conditions. These trends suggest that the onset of discrete aurora is controlled by the processes that govern the interaction between the draped IMF and the crustal magnetic anomalies. Here, we analyze MAVEN magnetometer measurements over regions of strong crustal fields during 49 discrete auroral events observed by IUVS. Our results indicate that the draped IMF orientations during each discrete auroral event show a clear tendency to be anti-parallel to the underlying crustal anomaly magnetic fields near the location of the emission onset. This suggests that magnetic reconnection, a process that favors anti-parallel magnetic field regimes, between the crustal fields and the draped IMF plays a role in discrete aurora formation. Of the 49 discrete auroral events analyzed, 42 (86%) occurred under draped IMF conditions that are susceptible to reconnection with the underlying crustal anomalies. This investigation produces strong evidence linking discrete aurora to magnetic reconnection at Mars and provides insights into other trends in discrete auroral activation such as local time and upstream IMF conditions.

Muon Flux Variations Measured by Low‐Cost Portable Cosmic Ray Detectors and Their Correlation With Space Weather Activity

Wed, 12/20/2023 - 12:58
Abstract

We present a comparison of the measured cosmic ray (CR) muon fluxes from two identical portable low-cost detectors at different geolocations and their sensitivity to space weather events in real time. The first detector is installed at Mount Wilson Observatory, CA, USA (geomagnetic cutoff rigidity Rc ∼ 4.88 GV), and the second detector is running on the downtown campus of Georgia State University in Atlanta, GA, USA (Rc ∼ 3.65 GV). The variation of the detected muon fluxes is compared to the changes in the interplanetary solar wind parameters at the L1 Lagrange point and geomagnetic indexes. In particular, we have investigated the muon flux behavior during three major interplanetary shock events and geomagnetic disturbances that occurred during July and August of 2022. To validate the interpretation of the measured muon signals, we compare the muon fluxes to the measurement from the Oulu neutron monitor (NM, Rc ∼ 0.8 GV). The results of this analysis show that the muon detector installed at Mount Wilson Observatory demonstrates a stronger correlation with a high-latitude NM. Both detectors typically observe a muon flux decrease during the arrival of interplanetary shocks and geomagnetic storms. Interestingly, the decrease could be observed several hours before the onset of the first considered interplanetary shocks at L1 at 2022-07-23 02:28:00 UT driven by the high-speed Coronal Mass Ejection and related geomagnetic storm at 2022-07-23 03:59:00 UT. This effort represents an initial step toward establishing a global network of portable low-cost CR muon detectors for monitoring the sensitivity of muon flux changes to space and terrestrial weather parameters.

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