High Electron Flux Research Articles

ZnCdS/CoMoOS Photocatalyst with High Electron Flux at the Ternary Interface Enhances H2 production

ZnCdS/CoMoOS Photocatalyst with High Electron Flux at the Ternary Interface Enhances H₂ production

Plasma Observations in the Distant Magnetotail During Intervals of Northward IMF

AbstractWe examine a 6‐day traversal of the magnetotail by the ARTEMIS satellites during an interval of prolonged northward IMF. The electrostatic analyzer (ESA) onboard the ARTEMIS spacecraft measures high ion and electron fluxes at approximately 60 RE downtail in regions of the magnetotail which would normally be the magnetotail lobe, containing open flux evacuated of plasma. We interpret these observations as trapped plasma on closed magnetic flux indicating that the magnetotail is closed or partially closed but extends at least as far as ∼60 RE downtail. We find that the occurrence of plasma in the magnetotail and the closure of the magnetosphere results in distinct changes to the magnetotail structure including a reduction in the magnetic field strength and pressure as well as a narrowing of the tail by approximately 20 RE.

Experimental and theoretical evidence for unprecedented strong interactions of gold atoms with boron on boron/sulfur-doped carbon surfaces.

The 16e square-planar bis-thiolato-Au(iii) complexes [AuIII(1,2-dicarba-closo-dodecarborane-1,2-dithiolato)2][NBu4] (Au-1) and [AuIII(4-methyl-1,2-benzenedithiolato)2][NBu4] (Au-2) have been synthesized and fully characterized. Au-1 and Au-2 were encapsulated in the symmetrical triblock copolymer poloxamer (Pluronic®) P123 containing blocks of poly(ethylene oxide) and poly(propylene oxide), giving micelles AuMs-1 and AuMs-2. High electron flux in scanning transmission electron microscopy (STEM) was used to generate single gold atoms and gold nanocrystals on B/S-doped graphitic surfaces, or S-doped amorphous carbon surfaces from AuMs-1 and AuMs-2, respectively. Electron energy loss spectroscopy (EELS) data suggested strong interactions of gold atoms/nanocrystals with boron in the B/S-doped graphitic matrix. Density-functional theory (DFT) calculations, also supported the experimental findings, pointing towards strong Au-B bonds, depending on the charge on the Au-(B-graphene) fragment and the presence of further defects in the graphene lattice.

Detection of large-scale synchrotron radiation from the molecular envelope of the Sgr B cloud complex at the Galactic centre

ABSTRACT We present highly sensitive measurements taken with MeerKAT at 1280 MHz as well as archival Green Bank Telescope (GBT), Murchison Widefield Array, and Very Large Array (VLA) images at 333, 88, and 74 MHz. We report the detection of synchrotron radio emission from the infrared dark cloud associated with the halo of the Sgr B complex on a scale of ∼60 pc. A strong spatial correlation between low-frequency radio continuum emission and dense molecular gas, combined with spectral index measurements, indicates enhanced synchrotron emission by cosmic ray electrons. Correlation of the Fe i 6.4 keV K α line and synchrotron emission provides compelling evidence that the low energy cosmic ray electrons are responsible for producing the K α line emission. The observed synchrotron emission within the halo of the Sgr B cloud complex has a mean spectral index α ∼ −1 ± 1, which gives the magnetic field strength ∼100 µG for cloud densities nH = 104–105 cm−3, and estimated cosmic ray ionization rates between 10−13 and 10−14 s−1. Furthermore, the energy spectrum of primary cosmic ray electrons is constrained to be E−3 ± 1 for typical energies of few hundred MeV. The extrapolation of this spectrum to higher energies is consistent with X-ray and γ-ray emission detected from this cloud. These measurements have important implications on the role that high cosmic ray electron fluxes at the Galactic centre play in production of radio synchrotron emission, the Fe i K α line emission at 6.4 keV, and ∼GeV γ-ray emission throughout the Central Molecular Zone.

Electron flux is a key determinant of uranium isotope fractionation during bacterial reduction

Uranium isotopic signatures in the rock record are utilized as a proxy for past redox conditions on Earth. However, these signatures display significant variability that complicates the interpretation of specific redox conditions. Using the model uranium-reducing bacterium, Shewanella oneidensis MR-1, we show that the abundance of electron donors (e.g., labile organic carbon) controls uranium isotope fractionation, such that high electron fluxes suppress fractionation. Further, by purifying a key uranium-reducing enzyme, MtrC, we show that the magnitude of fractionation is explicitly controlled by the protein redox state. Finally, using a mathematical framework, we demonstrate that these differences in fractionation arise from the propensity for back-reaction throughout the multi-step reduction of hexavalent uranium. To improve interpretations of observed fractionations in natural environments, these findings suggest that a variable intrinsic fractionation factor should be incorporated into models of uranium isotope systematics to account for differences in electron flux caused by organic carbon availability.

Interpretation of the North‐South Asymmetric Oxygen Aurora Morphology on Europa Using Test Particle Simulation

AbstractSeveral observations using the Hubble Space Telescope reported that the brightness morphology of the oxygen OI] 135.6 nm emissions on Europa's atmosphere has a north‐south asymmetry which changes with the position of Europa with respect to the Jovian magnetospheric plasma sheet. Similar north‐south asymmetry of Io's auroral limb glow has been explained by higher electron flux into the atmosphere on the hemisphere that faces the plasma sheet center. This explanation, however, has not yet been evaluated for the case of Europa quantitatively. In this study, we used a test particle simulation for the Jovian magnetospheric electrons to estimate the brightness of the 135.6 nm aurora in Europa's atmosphere and evaluate the cause of the north‐south asymmetry with the previously suggested idea, in which the strong deceleration of the magnetospheric flux tube results in the inhomogeneous electron flux into Europa's atmosphere (the “slow‐down effect”). Our simulation successfully recreates the systematically changing north‐south asymmetry of Europa's oxygen aurora brightness using the “slow‐down effect.” With deceleration into 10% of the background plasma flow, the maximum north‐to‐south brightness ratio is estimated at 2.17 and 2.56 on the trailing (plasma‐upstream) and leading (downstream) side, respectively. However, the previously observed brightness ratio is larger on the trailing side (up to ∼5). The results indicate that additional model scenarios are required to fully explain the north‐south asymmetry of Europa's oxygen aurora morphology.

Goethite Mineral Dissolution to Probe the Chemistry of Radiolytic Water in Liquid-Phase Transmission Electron Microscopy.

Liquid-Phase Transmission Electron Microscopy (LP-TEM) enables in situ observations of the dynamic behavior of materials in liquids at high spatial and temporal resolution. During LP-TEM, incident electrons decompose water molecules into highly reactive species. Consequently, the chemistry of the irradiated aqueous solution is strongly altered, impacting the reactions to be observed. However, the short lifetime of these reactive species prevent their direct study. Here, the morphological changes of goethite during its dissolution are used as a marker system to evaluate the influence of radiation on the changes in solution chemistry. At low electron flux density, the morphological changes are equivalent to those observed under bulk acidic conditions, but the rate of dissolution is higher. On the contrary, at higher electron fluxes, the morphological evolution does not correspond to a unique acidic dissolution process. Combined with kinetic simulations of the steady state concentrations of generated reactive species in the aqueous medium, the results provide a unique insight into the redox and acidity interplay during radiation induced chemical changes in LP-TEM. The results not only reveal beam-induced radiation chemistry via a nanoparticle indicator, but also open up new perspectives in the study of the dissolution process in industrial or natural settings.

High heat flux reduction to materials using current filaments

Reducing high electron and ion heat fluxes is one of the critical issues for shielding satellites and spacecraft. One of the ideas for shielding high particle and heat fluxes is to apply an external magnetic field generated by injecting current filaments. In this work, we model a flow of plasma, which includes electrons and ions in a small region, by using two spatial dimensions and three coordinates for velocities (2D3V) Particle-In-Cell (PIC) code to study the effects of the injected current filaments on particle and heat fluxes to the wall. The plasma enters the simulation domain from the source region at the left boundary and is fully absorbed in the conductor wall at the right boundary. Current filaments are injected to change the magnetic field structure of the system. We compare particle density, particle flux, and heat flux with and without injecting the current filaments into the domain in two dimensions. Based on the simulation results, we found that injecting current filaments can reduce the peak fluxes to the wall and transfer some of those fluxes along the wall. Therefore, injecting the current filaments is a good candidate for shielding satellites and spacecraft from high-energy ion and electron fluxes.

EELS Studies of Cerium Electrolyte Reveal Substantial Solute Concentration Effects in Graphene Liquid Cells.

Graphene liquid cell transmission electron microscopy is a powerful technique to visualize nanoscale dynamics and transformations at atomic resolution. However, the solution in liquid cells is known to be affected by radiolysis, and the stochastic formation of graphene liquid cells raises questions about the solution chemistry in individual pockets. In this study, electron energy loss spectroscopy (EELS) was used to evaluate a model encapsulated solution, aqueous CeCl3. First, the ratio between the O K-edge and Ce M-edge was used to approximate the concentration of cerium salt in the graphene liquid cell. It was determined that the ratio between oxygen and cerium was orders of magnitude lower than what is expected for a dilute solution, indicating that the encapsulated solution is highly concentrated. To probe how this affects the chemistry within graphene liquid cells, the oxidation of Ce3+ was measured using time-resolved parallel EELS. It was determined that Ce3+ oxidizes faster under high electron fluxes, but reaches the same steady-state Ce4+ concentration regardless of flux. The time-resolved concentration profiles enabled direct comparison to radiolysis models, which indicate rate constants and g-values of certain molecular species are substantially different in the highly concentrated environment. Finally, electron flux-dependent gold nanocrystal etching trajectories showed that gold nanocrystals etch faster at higher electron fluxes, correlating well with the Ce3+ oxidation kinetics. Understanding the effects of the highly concentrated solution in graphene liquid cells will provide new insight on previous studies and may open up opportunities to systematically study systems in highly concentrated solutions at high resolution.

Electron-Enhanced Atomic Layer Deposition of Titanium Nitride Films Using an Ammonia Reactive Background Gas

Electron-enhanced atomic layer deposition (EE-ALD) of titanium nitride (TiN) films was achieved using sequential exposures of tetrakis(dimethylamido)titanium (TDMAT) and low energy electrons in the presence of a continuous NH3 reactive background gas (RBG). Performing EE-ALD concurrently with a RBG is a new ALD film growth technique. The TiN EE-ALD was performed utilizing a hollow cathode plasma electron source (HC-PES). The HC-PES can deliver a high electron flux into background gases at pressures up to several mTorr. The TiN EE-ALD was conducted at temperatures of 30–70 °C using an electron acceleration voltage of 100 V and a NH3 pressure of ∼1 mTorr. The incident electron flux promotes electron stimulated desorption (ESD) and facilitates rapid nucleation and low temperature film growth. The TiN EE-ALD film growth was achieved on a variety of substrates including a native oxide on silicon, a SiO2 thermal oxide, and in situ silicon nitride films grown using electron-enhanced chemical vapor deposition (EE-CVD). Growth rates of 0.75 to 1.8 Å per cycle were measured using in situ four-wavelength ellipsometry for different TDMAT precursor exposures. Ex situ X-ray photoelectron spectroscopy (XPS) studies indicated that the TiN films were high purity and slightly nitrogen-rich. The in situ ellipsometry also measured low resistivities of ∼120 μΩ cm for the TiN films with thicknesses of ≥60 Å. These low resistivities were confirmed by ex situ four-point probe measurements and ex situ spectroscopic ellipsometry. X-ray diffraction investigations determined that the TiN EE-ALD films were crystalline. X-ray reflectivity studies also indicated that the thin TiN films had densities similar to bulk films. The high quality of the TiN EE-ALD films is attributed to the NH3 RBG. Interaction between the low energy electrons and the NH3 RBG is believed to form •NH2 and •H radical species that react with the surface during EE-ALD and improve film purity. The reactive •NH2 and •H species likely lead to nitridation and carbon removal from the films. RBGs greatly expand the possibilities for tuning film composition and properties during EE-ALD. In addition, TiN EE-ALD was accomplished on insulating substrates such as an SiO2 thermal oxide. The TiN EE-ALD is believed to be possible on insulating substrates because the secondary electron yield for electron energies of ∼100 eV is greater than unity.

A Climatology of Long-Duration High 2-MeV Electron Flux Periods in the Outer Radiation Belt.

Since the advent of the Space Age, the importance of understanding and forecasting relativistic electron fluxes in the Earth’s radiation belts has been steadily growing due to the threat that such particles pose to satellite electronics. Here, we provide a model of long‐duration periods of high time‐integrated 2‐MeV electron flux deep inside the outer radiation belt, based on the significant correlation obtained in 2001–2017 between time‐integrated electron flux measured by satellites and a measure of the preceding time‐integrated homogenized aa H geomagnetic index. We show that this correlation is likely due to a stronger cumulative chorus wave‐driven acceleration of relativistic electrons and a stronger cumulative inward radial diffusion of such electrons during periods of higher time‐integrated geomagnetic activity. Return levels of 2‐MeV electron flux are provided based on Extreme Value analysis of time‐integrated geomagnetic activity over 1868–2017, in rough agreement with estimates based on 20‐year data sets of measured flux. A high correlation is also found between our measure of time‐integrated geomagnetic activity averaged over each solar cycle and averaged sunspot numbers, potentially paving the way for forecasts of time‐integrated relativistic electron flux during future solar cycles based on predictions of solar activity.

Warm protons at comet 67P/Churyumov–Gerasimenko – implications for the infant bow shock

Abstract. The plasma around comet 67P/Churyumov–Gerasimenko showed remarkable variability throughout the entire Rosetta mission. Plasma boundaries such as the diamagnetic cavity, solar wind ion cavity and infant bow shock separate regions with distinct plasma parameters from each other. Here, we focus on a particular feature in the plasma: warm, slow solar wind protons. We investigate this particular proton population further by focusing on the proton behaviour and surveying all of the Rosetta comet phase data. We find over 300 events where Rosetta transited from a region with fast, cold protons into a region with warm, slow protons. We investigate the properties of the plasma and magnetic field at this boundary and the location where it can be found. We find that the protons are preferentially detected at intermediate gas production rates with a slight trend towards larger cometocentric distances for higher gas production rates. The events can mostly be found in the positive convective electric field hemisphere. These results agree well with simulations of the infant bow shock (IBS), an asymmetric structure in the plasma environment previously detected on only 2 d during the comet phase. The properties of the plasma on both sides of this structure are harder to constrain, but there is a trend towards higher electron flux, lower magnetic field, higher magnetic field power spectral density and higher density in the region that contains the warm protons. This is in partial agreement with the previous IBS definitions; however, it also indicates that the plasma and this structure are highly non-stationary. For future research, Comet Interceptor, with its multi-point measurements, can help to disentangle the spatial and temporal effects and give more clarity on the influence of changing upstream conditions on the movement of boundaries in this unusual environment.

Constraints on dark matter annihilation from several IACTs’ cosmic ray electron spectrums

In dark matter self-annihilation events, highly energetic electron and positron pairs can be created in several different annihilation channels and propagate through space while losing their energies. The electrons can lose their energies by these mechanisms; the interaction with low-energy photons via inverse Compton scattering, synchrotron radiation due to interstellar magnetic fields, and ionization with neutral hydrogen atoms, resulting in high energy cosmic electron fluxes at the Earth’s location. Adopted electron spectrums from H. E. S. S., MAGIC, and VERITAS which are Imaging Atmospheric Cherenkov Telescopes (IACTs), we have found the constraints on dark matter annihilation in a range of TeV energies. The results show the stringent constraint on electron channels, and there are no significant differences in constraints between IACTs’ data sets.

Dual crystallization modes of sputter-deposited amorphous SiGe films

The crystallization behavior of sputter-deposited films of amorphous Si (a-Si) and SiGe alloys (a-SiGe) induced by electron irradiation at room temperature and by thermal annealing was investigated by in situ transmission electron microscopy. On electron irradiation at room temperature, extremely rapid crystallization, so-called explosive crystallization, occurred at a higher electron flux but not at a lower electron flux. On in situ thermal annealing, explosive crystallization occurred preferentially and partially at low temperatures in Ge-rich a-SixGe100−x for x < 50 but not for x > 50. These results indicate that the increase of Si content in a-SiGe prevents the occurrence of explosive crystallization. We previously proposed that explosive crystallization can occur in pristine a-Ge films via the interface of a liquid-like, high-density amorphous state at the growth front. An increase in the instability of this high-density amorphous state caused by the increase of Si in a-SiGe apparently gives rise to the suppression of explosive crystallization.

One–step reductive synthesis of Ti3+ self–doped elongated anatase TiO2 nanowires combined with reduced graphene oxide for adsorbing and degrading waste engine oil

A sustainable photocatalyst of Ti3+ self-doped elongated anatase nanowires combined with reduced graphene oxide (TiO2 NWs@rGO) was prepared via a facile one-step reductive synthesis process using NaBH4 as reductant for the first time. The obtained optimal TiO2 NWs@rGO composite has a large surface area,182 m2 g-1, which demonstrates strong adsorption capacity due to the multilayered structure built by highly crystallized nanowires of TiO2 and ultrathin rGO layers. When the photocatalyst was applied in removing waste engine oil (100 mL, 50 mg L-1), it exhibited outstanding performance with up to COD 98.6% removal extent (from 145 initial to 2 mg L-1 final COD) after 5 h, which is 34.1% higher than that of TiO2 NWs (64.5% COD removal extent). Gas chromatography-mass spectrometry analyses of residual waste engine oil after photocatalysis shows significant reductions of C6-C19 chemicals as well as total disappear of C15,C16, C17, C18 chemicals. The outstanding photocatalytic activity of TiO2 NWs@rGO benefits from sensitive response to visible light, improved surface reactivity and high electron flux enabled by rGO and Ti3+ in TiO2. In addition, this composite catalyst can be self-cleaned, and recycled for reuse, which suggests promising potential for waste engine oil treatment.

Properties of Whistler Mode Waves in Earth's Plasmasphere and Plumes

AbstractWhistler mode wave properties inside the plasmasphere and plumes are systematically investigated using 5‐year data from Van Allen Probes. The occurrence and intensity of whistler mode waves in the plasmasphere and plumes exhibit dependences on magnetic local time, L, and AE. Based on the dependence of the wave normal angle and Poynting flux direction on L shell and normalized wave frequency to electron cyclotron frequency (fce), whistler mode waves are categorized into four types. Type I: ~0.5 fce with oblique wave normal angles mostly in plumes; Type II: 0.01–0.5 fce with small wave normal angles in the outer plasmasphere or inside plumes; Type III: <0.01 fce with oblique wave normal angles mostly within the plasmasphere or plumes; Type IV: 0.05–0.5 fce with oblique wave normal angles deep inside the plasmasphere. The Poynting fluxes of Type I and II waves are mostly directed away from the equator, suggesting local amplification, whereas the Poynting fluxes of Type III and IV are directed either away from or toward the equator, and may originate from other source regions. Whistler mode waves in plumes have relatively small wave normal angles with Poynting flux mostly directed away from the equator and are associated with high electron fluxes from ~30 keV to hundreds of keV, all of which support local amplification. Whistler mode wave amplitudes in plumes can be stronger than typical plasmaspheric hiss, particularly during active times. Our results provide critical insights into understanding whistler mode wave generation inside the plasmasphere and plumes.

Metatranscriptomic Investigation of Adaptation in NO and N2O Production From a Lab-Scale Nitrification Process Upon Repeated Exposure to Anoxic-Aerobic Cycling.

The molecular mechanisms of microbial adaptation to repeated anoxic–aerobic cycling were investigated by integrating whole community gene expression (metatranscriptomics) and physiological responses, including the production of nitric (NO) and nitrous (N2O) oxides. Anoxic–aerobic cycling was imposed for 17 days in a lab-scale full-nitrification mixed culture system. Prior to cycling, NO and N2O levels were sustained at 0.097 ± 0.006 and 0.054 ± 0.019 ppmv, respectively. Once the anoxic–aerobic cycling was initiated, peak emissions were highest on the first day (9.8 and 1.3 ppmv, respectively). By the end of day 17, NO production returned to pre-cycling levels (a peak of 0.12 ± 0.007 ppmv), while N2O production reached a new baseline (a peak of 0.32 ± 0.05 ppmv), one order of magnitude higher than steady-state conditions. Concurrently, post-cycling transcription of norBQ and nosZ returned to pre-cycling levels after an initial 5.7- and 9.5-fold increase, while nirK remained significantly expressed (1.6-fold) for the duration of and after cycling conditions. The imbalance in nirK and nosZ mRNA abundance coupled with continuous conversion of NO to N2O might explain the elevated post-cycling baseline for N2O. Metatranscriptomic investigation notably indicated possible NO production by NOB under anoxic–aerobic cycling through a significant increase in nirK expression. Opposing effects on AOB (down-regulation) and NOB (up-regulation) CO2 fixation were observed, suggesting that nitrifying bacteria are differently impacted by anoxic–aerobic cycling. Genes encoding the terminal oxidase of the electron transport chain (ccoNP, coxBC) were the most significantly transcribed, highlighting a hitherto unexplored pathway to manage high electron fluxes resulting from increased ammonia oxidation rates, and leading to overall, increased NO and N2O production. In sum, this study identified underlying metabolic processes and mechanisms contributing to NO and N2O production through a systems-level interrogation, which revealed the differential ability of specific microbial groups to adapt to sustained operational conditions in engineered biological nitrogen removal processes.

Kinetic Understanding of N2 Reduction versus H2 Evolution at the E4(4H) Janus State in the Three Nitrogenases.

The enzyme nitrogenase catalyzes the reduction of N2 to ammonia but also that of protons to H2. These reactions compete at the mechanistically central 'Janus' intermediate, denoted E4(4H), which has accumulated 4e-/4H+ as two bridging Fe-H-Fe hydrides on the active-site cofactor. This state can lose e-/H+ by hydride protonolysis (HP) or become activated by reductive elimination ( re) of the two hydrides and bind N2 with H2 loss, yielding an E4(2N2H) state that goes on to generate two NH3 molecules. Thus, E4(4H) represents the key branch point for these competing reactions. Here, we present a steady-state kinetic analysis that precisely describes this competition. The analysis demonstrates that steady-state, high-electron flux turnover overwhelmingly populates the E4 states at the expense of less reduced states, quenching HP at those states. The ratio of rate constants for E4(4H) hydride protonolysis ( kHP) versus reductive elimination ( kre) provides a sensitive measure of competition between these two processes and thus is a central parameter of nitrogenase catalysis. Analysis of measurements with the three nitrogenase variants (Mo-nitrogenase, V-nitrogenase, and Fe-nitrogenase) reveals that at a fixed N2 pressure their tendency to productively react with N2 to produce two NH3 molecules and an accompanying H2, rather than diverting electrons to the side reaction, HP production of H2, decreases with their ratio of rate constants, k re/ kHP: Mo-nitrogenase, 5.1 atm-1; V-nitrogenase, 2 atm-1; and Fe-nitrogenase, 0.77 atm-1 (namely, in a 1:0.39:0.15 ratio). Moreover, the lower catalytic effectiveness of the alternative nitrogenases, with more H2 production side reaction, is not caused by a higher kHP but by a significantly lower k re.

On the Role of Last Closed Drift Shell Dynamics in Driving Fast Losses and Van Allen Radiation Belt Extinction

AbstractWe present observations of very fast radiation belt loss as resolved using high time resolution electron flux data from the constellation of Global Positioning System (GPS) satellites. The time scale of these losses is revealed to be as short as ∼0.5–2 hr during intense magnetic storms, with some storms demonstrating almost total loss on these time scales and which we characterize as radiation belt extinction. The intense March 2013 and March 2015 storms both show such fast extinction, with a rapid recovery, while the September 2014 storm shows fast extinction but no recovery for around 2 weeks. By contrast, the moderate September 2012 storm which generated a three radiation belt morphology shows more gradual loss. We compute the last closed drift shell (LCDS) for each of these four storms and show a very strong correspondence between the LCDS and the loss patterns of trapped electrons in each storm. Most significantly, the location of the LCDS closely mirrors the high time resolution losses observed in GPS flux. The fast losses occur on a time scale shorter than the Van Allen Probes orbital period, are explained by proximity to the LCDS, and progress inward, consistent with outward transport to the LCDS by fast ultralow frequency wave radial diffusion. Expressing the location of the LCDS in L*, and not model magnetopause standoff distance in units of RE, clearly reveals magnetopause shadowing as the cause of the fast loss observed by the GPS satellites.

Electron Fluxes at Geostationary Orbit From GOES MAGED Data

AbstractElectron behavior in energies below 200 keV at geostationary orbit has significance for satellite operations due to charging effects on spacecraft. Five years of keV energy electron measurements by the geostationary GOES‐13 satellite's MAGnetospheric Electron Detector (MAGED) instrument has been analyzed. A method for determining flight direction integrated fluxes is presented. The electron fluxes at the geostationary orbit are shown to have significant dependence on solar wind speed and interplanetary magnetic field (IMF) BZ: increased solar wind speed correlates with higher electron fluxes with all magnetic local times while negative IMF BZ increases electron fluxes in the 0 to 12 magnetic local time sector. A predictive empirical model for electron fluxes in the geostationary orbit for energies 40, 75, and 150 keV was constructed and is presented here. The empirical model is dependent on three parameters: magnetic local time, solar wind speed, and IMF BZ.