Abstract We quantify the electron scattering effects of simultaneous plasmaspheric hiss and magnetosonic waves that occurred in two neighboring time intervals but with distinct wave intensity profiles on 21 August 2013. Their combined is found capable causing distribution variations largely distinguishable from consequences individual waves. The net effect diffusion relies strongly relative dominance intensities, which also controls contribution each mode. In combination, MS slow down...

Abstract Very-Low-Frequency (VLF) transmitters operate worldwide mostly at frequencies of 10–30 kilohertz for submarine communications. While it has been intense scientific interest and practical importance to understand whether VLF can affect the natural environment charged energetic particles, decades there remained little direct observational evidence that revealed effects these in geospace. Here we report a radially bifurcated electron belt formation energies tens kiloelectron volts...

Abstract We investigate the outer radiation belt electron energy spectra of highest fluxes observed during storms based on Van Allen Probes measurements, which demonstrate a similar shape despite various levels geomagnetic activity. Using quasi‐linear diffusion simulations, we reproduce acceleration by whistler‐mode chorus waves storm 25 October 2016, when maximum were close to upper limit 2013–2018 period. The electrons below ∼1 MeV reached within day and then remained at stable level,...

Abstract We investigate the response of outer radiation belt electron fluxes to different solar wind and geomagnetic indices using an interpretable machine learning method. reconstruct flux variation during 19 enhancement 7 depletion events demonstrate feature attribution analysis called SHAP (SHapley Additive exPlanations) on superposed epoch results for first time. find that intensity duration substorm sequence following initial dropout determine overall or fluxes, while pressure drives in...

Abstract We perform ensemble simulations of radiation belt electron acceleration using the quasi‐linear approach during storm on 9 October 2012, where chorus waves dominated at L = 5.2. Based a superposed epoch analysis 11 similar storms when both multi‐MeV flux enhancements and wave activities were observed by Van Allen Probes, we use percentiles to sample normalized input distributions for four key inputs estimate their relative perturbations. Using points in each parameter including...

Abstract Energetic electron precipitation (EEP) associated with pulsating aurora can transfer greater than 30 keV electrons from the outer radiation belt region into upper atmosphere and deplete atmospheric ozone via collisions that produce NOx HOx molecules. Our knowledge of exactly how EEP occurs is incomplete. Previous studies have shown pitch angle scattering between lower‐band chorus waves cause substorms play an important role. In this work, we quantify timescale wave decay following...

Abstract Whistler mode hiss acts as an important loss mechanism contributing to the radiation belt electron dynamics inside plasmasphere and plasmaspheric plumes. Based on Van Allen Probes observations from September 2012 December 2015, we conduct a detailed analysis of properties in plumes illustrate that corresponding highest occurrence probability at L = 5.0–6.0 MLT 18–21, emissions occur concurrently with rate >~80%. Plume can efficiently scatter ~10‐ 100‐keV electrons rates up ~10 −4...

Abstract Plasmaspheric hiss is known to play an important role in radiation belt electron dynamics high plasma density regions. We present observations of two crossings a plasmaspheric plume by the Van Allen Probes on 26 December 2012, which occurred unusually at post‐midnight‐to‐dawn sector between L ~ 4–6 during geomagnetically quiet period. This exhibited pronounced densities higher than those average level. Moderate emissions accompanied with peak power about 100 Hz. Quantification...

Abstract We investigate the statistical distribution of upper limit outer radiation belt electron fluxes during active times using 5‐year measurements from Van Allen Probes. The flux at different energies peaks around L ∼ 4.7, with larger variation higher >1 MeV compared to hundreds keV. Based on correlation analysis between maximum and various time‐integrated geomagnetic indices, including SYM‐H, AE, AL, we reveal that strongly correlate cumulative effects substorms instead storms,...

Since the discovery of Earth’s radiation belts in 1958, it has always been a challenge to determine dominant physical mechanisms, whether local acceleration by chorus or inward radial diffusion, that leads outer belt relativistic electron flux enhancements. In this study, we test chain processes with several potential successive steps is believed accelerate electrons. By performing correlation analysis different part chain, including geomagnetic condition, evolution source and seed fluxes,...

The forensic examination of AIGC(Artificial Intelligence Generated Content) faces poses a contemporary challenge within the realm color image forensics. A myriad artificially generated by AIGC encompasses both global and local manipulations. While there has been noteworthy progress in scrutiny fake faces, current research primarily focuses on isolated detection globally locally manipulated thus lacking universally effective methodology. To address this limitation, we propose sophisticated...

Abstract We report a new population of outer belt electron acceleration events ranging from hundreds keV to ∼1.5 MeV that occurred inside the plasmasphere, which we named “Inside Events” (IEs). Based on 6 year observations Van Allen Probes, compare statistical distributions IEs with outside plasmasphere (OEs). find most were observed at L < 4.0 energies below MeV, weaker ratio (<10) and larger event numbers (peaking value reaching >200), compared stronger but less frequently only...

Abstract Both magnetosonic (MS) waves and plasmaspheric hiss can resonantly scatter outer radiation belt electrons, leading to various electron pitch angle distribution. Based on diffusion coefficients calculations 2‐D Fokker‐Planck simulations, we perform a parametric study quantitatively investigate the net scattering effect relative contributions of simultaneously occurring MS with groups different wave amplitude combinations. It is found that combined effects are dominated by due...

Radiation belt electron dropouts indicate flux decay to the background level during geomagnetic storms, which is commonly attributed effects of wave-induced pitch angle scattering and magnetopause shadowing. To investigate loss mechanisms radiation triggered by a solar wind dynamic pressure pulse event on 12 September 2014, we comprehensively analyzed particle wave measurements from Van Allen Probes. The dropout was divided into three periods: before storm, initial phase main storm....

It has become well-established that strong outer radiation belt enhancements are due to wave-driven electron energization by whistler-mode chorus waves. However, in this study, we examine MeV injections on 10 July 2019 and find substantial evidence such may be a crucial contributor enhancement events. For an examination, it is essential precisely separate temporal flux changes from spatial variations observed as Van Allen Probes move along their orbits. Employing new “hourly snapshot”...

Abstract Magnetosonic (MS) waves have been found capable of creating radiation belt electron butterfly distributions in the inner magnetosphere. To investigate physical nature interactions between electrons and MS waves, to explore a preferential condition for scatter efficiently, we performed comprehensive parametric study wave‐electron using test particle simulations. The diffusion coefficients simulated by varying wave frequency show that scattering effect is insensitive at low harmonics...

Abstract Using 5‐year of measurements from Van Allen Probes, we present a survey the statistical dependence Earth's outer radiation belt electron flux dropouts during geomagnetic storms on energy and various driving parameters including interplanetary magnetic field B z , P SW SYM‐H, AE. By systematically investigating over energies 1 keV–10 MeV at L‐shells spanning 4.0–6.5, find that are naturally divided into three regions. The show much higher occurrence rates below ∼100 keV above ∼1...

Abstract We report a typical event that fast magnetosonic (MS) waves, exohiss, and two‐band chorus waves occurred simultaneously on the dayside observed by Van Allen Probes 25 December 2013. By combining calculations of electron diffusion coefficients 2‐D Fokker‐Planck simulations, we quantitatively analyze combined scattering effect multiple to demonstrate net impact does not simply depend wave intensity dominance various plasma waves. Although MS are most intense, butterfly distribution is...

Abstract Based on Van Allen Probes observations, in this study we perform a statistical analysis of the spectral intensities plasmaspheric hiss at L‐shells 1.8–3.0 slot region. Our results show that region power intensifies with strong day‐night asymmetry as level substorm activity or L‐shell increases. Using profiles hiss, calculate drift‐ and bounce‐averaged electron pitch angle diffusion coefficients subsequently obtain resultant loss timescales through 1‐D Fokker‐Planck simulations. We...

Abstract We perform a comprehensive investigation of the statistical distribution outer belt electron acceleration events over energies from 300 keV to ∼10 MeV regardless storm activity using 6‐years observations Van Allen Probes. find that properties are consistent with characteristic combined local by chorus waves and inward radial diffusion. While frequently occur both at <2 L < 4.0 multi‐MeV > 4.5, significant confined ∼4.0. By performing superposed epoch analysis during...

Abstract Recent studies have reported the simultaneous observation of Magnetosonic (MS) waves and Electromagnetic ion cyclotron (EMIC) waves. In this study, a detailed survey concurrent EMIC MS is performed using Van Allen Probes observations from 2012 to 2017. The results suggest that most are H + band favorable geomagnetic conditions for AE* ≥ 500 nT inside plasmapause 100 outside plasmapause. Although generally stronger than waves, more likely occur during moderate active times. Our study...

Abstract The very‐low frequency (VLF) and low (LF) waves from ground transmitters propagate in the ionospheric waveguide, a portion of their power leaks to Earth's inner radiation belt slot region where it can cause electron precipitation loss. Using Van Allen Probes observations, we perform survey VLF LF transmitter at frequencies 14 200 kHz. statistical electric magnetic wave amplitudes spectra are obtained 1 < L 3. Based on recent study propagation waves, divide total into ducted...

Abstract We analyze an energetic electron flux enhancement event in the inner radiation belt observed by Van Allen Probes during intense geomagnetic storm. The at L~1.5 increased a factor of 3 with pronounced butterfly pitch angle distributions (PADs). Using three‐dimensional model, we simulate evolution under impact radial diffusion, local wave‐particle interactions including hiss, very low frequency transmitters, and magnetosonic waves, as well Coulomb scattering. Consistency between...

Ground-based very low frequency (VLF) transmitters located around the world generate signals that leak through bottom side of ionosphere in form whistler mode waves. Wave and particle measurements on satellites have observed these man-made VLF waves can be strong enough to scatter trapped energetic electrons into pitch angle orbits, causing loss by absorption lower atmosphere. This precipitation process is greatly enhanced intentional amplification using a newly discovered called rocket...