Background Electron Density Research Articles

Investigation of Co‐Seismic Ionospheric Perturbations Generated by Shallow Earthquakes in the Chile Subduction Zone

AbstractThe Chile subduction zone is known to host megathrust earthquakes. This study investigates the near‐field co‐seismic ionospheric perturbations (CIP) associated with recent large to great, shallow depth (22–25 km) earthquakes that occurred in the Chile subduction zone. These earthquakes are (a) 16 September 2015, Mw 8.3 (EQ1) (b) 03 April 2014, Mw 7.7 (EQ2) (c) 01 April 2014, Mw 8.2 (EQ3) (d) 02 January 2011, Mw 7.1 (EQ4), and (e) 27 February 2010, Mw 8.8 (EQ5). Using the Global Navigation Satellite System (GNSS) measured total electron content (TEC), we found that despite the lower magnitude of EQ3 than EQ1 and EQ5, the CIP observed during EQ3 had higher amplitudes than that of EQ5 and EQ1. The amplitude of CIP also depends on non‐seismic parameters in addition to the concerning earthquake magnitude. The comparison of relative CIP amplitudes, in light of the non‐seismic parameters of the geomagnetic field and satellite geometry indicates that background electron density (due to different local times of earthquake occurrence) might contributed to CIP amplitudes. We believe that this thorough analysis leads to a better understanding of non‐seismic factors that can largely influence the CIP amplitudes apart from the earthquake magnitudes.

Investigation on Chasing and Interaction of Traveling Ionospheric Disturbances Based on Multi‐Instrument

AbstractIn this study, we use multi‐instrument observations (all‐sky imager (ASI), global navigation satellite system (GPS) receivers, digisonde) to study the interaction of nighttime medium‐scale traveling ionospheric disturbances (MSTIDs) on 13 November 2018. The most attractive aspect of this event is that the interaction appeared between two dark bands both propagated southwestward. The airglow observations show that the latter band moved faster and caught up with the former, and these two bands merged into a new one. The propagating characteristics and morphology of the MSTIDs changed during the interaction process. The simulations from the Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model (TIEGCM) suggested that the ionospheric background zonal winds and electron density distributions could play essential roles in the interaction of the MSTIDs. Moreover, the merging process might be associated with the electrostatic reconnection.

Numerical investigation of discharge evolution and breakdown characteristics of ArF excimer lasers

The corona bar induced pre–ionization is a crucial preliminary process in the operation of ArF excimer lasers, directly impacting the uniformity and stability of output laser. The ultraviolet corona pre–ionization, as the mainstream method, is tightly coupled with the main discharge process, which complicates analysis. Here, we establish a numerical model of a single pulse discharge incorporating an external circuit to analyze the pre–ionization process and its influence on the breakdown characteristics. (1) By adopting detailed input parameters of photoionization model, we observe uniform and dispersed plasma propagation from the corona bar to the main gap. (2) An artificial boundary condition is proposed to investigate the phenomenological effect of high–energy electrons emission, emphasizing the influence of surface discharge along the cathode. (3) The propagation and breakdown characteristics of the two pre–ionization setup methods, photoionization and background electron density, are compared numerically. This study enhances the understanding of the pre–ionization process in ArF excimer lasers and provides theoretical insights for their optimization and design.

Simulating the Earth's Outer Radiation Belt Electron Fluxes and Their Upper Limit: A Unified Physics‐Based Model Driven by the AL Index

AbstractUsing particle and wave measurements from the Van Allen Probes, a 2‐D Fokker‐Planck simulation model driven by the time‐integrated auroral index (AL) value is developed. Simulations for a large sample of 186 storm‐time events are conducted, demonstrating that the AL‐driven model can reproduce flux enhancement of the MeV electrons. More importantly, the relativistic electron flux enhancement is determined by the sustained strong substorm activity. Enhanced substorm activity results in increased chorus wave intensity and reduced background electron density, which creates the required condition for local electron acceleration by chorus waves to MeV energies. The appearance of higher energy electrons in radiation belts requires a higher level of cumulative AL activity after the storm commencement, which acts as a type of switch, turning on progressively higher energies for longer and more intense substorms, at critical thresholds.

Effect of the superthermal electrons on the heat flux through a magnetized sheath

A one-dimensional model, in which the ionization and collision are omitted in the Debye sheath region, is applied to investigate the effect of the superthermal electrons on the heat flux through a magnetized sheath. For different temperatures and concentrations of the superthermal electron, and magnitudes and directions of the magnetic field, the profiles of plasma parameters including ion density and flow velocity perpendicular to the wall, the background and superthermal electron densities, and sheath potential in the presheath region are calculated. The variation of the plasma density and sheath potential drop at the Debye sheath entrance with the superthermal electrons and magnetic field modifies the particle and heat fluxes across the Debye sheath to the material surface. The sheath heat transmission coefficient can increase significantly even for a very small superthermal electron population. The dependence of the sheath heat transmission coefficient on the magnetic field angle decreases with the contribution of the superthermal electron in a strong magnetized sheath. When investigation of the heat flux including the superthermal electrons to a water-cooled W/Cu monoblack for the tokamak divertor, compared to the case of without superthermal electrons, it is found that the increase in both heat flux to the material surface and surface temperature of the material is mainly due to the enhancement of the sheath potential drop caused by the superthermal electrons, but the increase in the latter is not as pronounced as the former.

Suprathermal Electron Transport in the Solar Wind: Effects of Coulomb Collisions and Whistler Turbulence

The nature and radial evolution of solar wind electrons in the suprathermal energy range are studied. A wave–particle interaction tensor and a Fokker–Planck Coulomb collision operator are introduced into the kinetic transport equation describing electron collisions and resonant interactions with whistler waves. The diffusion tensor includes diagonal and off-diagonal terms, and the Coulomb collision operator applies to arbitrary electron velocities describing collisions with both background protons and electrons. The background proton and electron densities and temperatures are based on previous turbulence models that mediate the supersonic solar wind. The electron velocity distribution functions and electron heat flux are calculated. Comparison and analysis of the numerical results with analytical solutions and observations in the near-Sun region are made. The numerical results reproduce well the creation of the sunward electron deficit observed in the near-Sun region. The deficit of the electron velocity distribution function below the core Maxwellian fit at low velocities results from Coulomb collisions, and the excess part above the core Maxwellian fit at high velocities is determined by strong wave–particle interactions.

Long‐Term Variations of Energetic Electrons Scattered by Signals From the North West Cape Transmitter

AbstractVery‐low‐frequency (VLF) signals emitted from ground‐based transmitters for submarine communication can penetrate the ionosphere and leak into the magnetosphere, leading to electron precipitation via wave‐particle interaction and thereby providing a potential means for radiation belt remediation. In this study, we systematically analyze the dependence of quasi‐trapped electron fluxes scattered by signals from the North West Cape (NWC) transmitter on electron energy, L‐shell, and geomagnetic activity (i.e., the Dst index) using long‐term measurements from the DEMETER satellite. Considering potentially changed theoretical cyclotron resonant condition, we find that the variations of wave normal angle (WNA) of NWC transmitter signals or of the background electron density can explain the variated “wisp” positions in energy versus L plane. The long‐term data analyzation suggests that the energy‐dependences increases can help to distinguish the different source mechanisms of quasi‐trapped electrons. The enhancement of quasi‐trapped electron fluxes induced by NWC transmitter signals is more obvious at L = 1.8 than L = 1.6 due to higher trapped flux levels and strong pitch angle diffusion induced by transmitter signals.

Simulation study on “Wisp” electron spectra generated by NWC very low frequency transmitter signals

Very low frequency (VLF) signals emitted by worldwide spread ground-based man-made transmitters mainly propagate in Earth-ionospheric waveguides and are used for submarine communication. A portion of these signals penetrate the ionosphere and leak into the magnetosphere when the ionospheric electron density decreases on the nightside due to the attenuated sunlight. The VLF transmitter signals in the magnetosphere can scatter electrons with energy of 100 Kev in the inner radiation belt into the drift loss cone through cyclotron resonance. This is an important loss mechanism for electrons in the inner radiation belt and plays an important role in transferring energy and mass from magnetosphere to ionosphere. Electrons scattered by transmitter signals exhibit a “wisp” characteristic in <i>L</i>-<i>E</i><sub><i>k</i></sub> spectrum, satisfying the first-order cyclotron resonance relationship between the electrons and the transmitter signals. The “wisp” spectrum can be clearly observed by low earth orbit satellites, presenting opportunities to study wave-particle interactions in near-Earth space. In this study, using the drift-diffusion-source model, we reproduce the “wisp” spectrum formed by scattering effects of NWC transmitter signals observed by DEMETER satellite on March 19, 2009. Our simulation results suggest that the equatorial pitch angle of electrons, observed by DEMETER, varies with the longitude, resulting in distinctions in the observed “wisp” spectrum along different longitudes. Specifically, as the satellite approaches South Atlantic Anomaly (SAA) region, both the energy range and flux level of the observed “wisp” spectrum gradually increase. When the previously studied wave normal angle model (with a central wave normal angle of 60°) and the background electron density model are used, the energy range of the simulated “wisp” spectra is higher than the observed value. Adjusting the central wave normal angle to 40° or increasing the background density by a factor of 1.3, the simulated results accord well with the observations. Our results elucidate the scattering effect of NWC transmitter signals on electrons in the radiation belt, and emphasize the importance of analyzing the formation of “wisp” spectrum for understanding wave-particle interactions in near-earth space. Additionally, the drift-diffusion-source model can be used to study wave-particle interactions in the inner radiation belt, providing an important basis for developing radiation belt remediation technology.

Seasonal dependence of the ionospheric heating effects under varied solar activity

As the annual variation of solar activity, the effect of ionospheric heating varies in a solar cycle. In this paper, we research the ionospheric heating at equinox and solstice with the modified SAMI2 model in the year within 23rd solar cycle. We find that except the F10.7 index, which play a critical role in the process of ionospheric heating, has a significant influence on the value of electron density, the distribution of the electron density also matters for the heating effects. In the year of 2003, a strong seasonal dependence can be found. But in other years of the same solar cycle, the seasonal dependence is not obvious. There may be a threshold for the electron density. When the ionospheric background electron density is less than the threshold, the ionospheric heating effects will be obvious. It can produce cavity structure of electron density and arc structure with enhanced electron density.

A Method for Estimating the Spatial Coherence of Mid‐Latitude Skywave Propagation Based on Transionospheric Scintillations at 35 MHz

AbstractThe results of a study aimed at assessing the utility of transionospheric 35 MHz scintillation measurements toward cosmic radio sources for estimating the level of spatial coherence in high frequency (HF) skywave systems are presented. An array of four antennas in southern Maryland called the Deployable Low‐band Ionosphere and Transient Experiment was used. Two of the antennas within a ∼350‐m north/south baseline were used to monitor 35‐MHz intensity variations of two bright cosmic sources, Cygnus A and Cassiopeia A. The other two antennas, which were within a ∼420‐m east/west baseline, recorded the 7.85 MHz skywave from the CHU radio station near Ottawa, Ontario. These HF measurements were used to quantify the level of spatial coherence by measuring the amplitudes of the cross correlation of the two antennas' recorded voltages relative to the received power, which were typically ∼0.5 to 0.9, but occasionally near zero. An approximate scaling method was developed to estimate the expected cross‐correlation amplitude based on the 35‐MHz scintillations. This method assumes a single layer of irregularities at the reflection height that affects relatively small changes in electron density, the latter of which is generally appropriate for mid‐latitudes. It also assumes that the irregularity distribution follows that of the background electron density. These calculations typically captured the day‐to‐day variations in spatial coherence well (correlation coefficient r ≃ 0.6) while only marginally reproducing hour‐to‐hour variations (r ≃ 0.2). Thus, this method holds promise as an economical and passive means to assess the spatial coherence expected for skywave propagation within a given mid‐latitude region.

Relationships between ionospheric parameters derived from ionosonde observations and characteristics of post-sunset GHz scintillation during high solar activities (2012−2013) at Sanya (18.3°N, 109.6°E), China

In this study, we presented the characteristics of post-sunset GHz scintillation occurrence and ionospheric parameters derived from ionosonde observations, including the critical frequency of F2-layer (foF2), peak height of F2-layer (hmF2), minimum virtual height of F-layer (h’F), scale height around the F2-layer peak (Hm), virtual height (h’F5) and true height (hF5) measured at 5 MHz, in high solar activity years (2012-2013) of solar cycle 24 at Sanya (18.3°N, 109.6°E; dip lat.: 12.8°N), China. Furthermore, we investigated the relationships between the equinoctial asymmetry of scintillation and these ionospheric parameters. In addition, the growth rates of Rayleigh-Taylor instability were calculated on the basis of the ionosonde measurements and models, respectively. The results showed that the equinoctial asymmetry of scintillation onset time would be associated with the scale length of vertical electron density gradient (L), which affects the growth of Rayleigh-Taylor instability at the bottom of F-layer. The seasonal variations of foF2, Hm and scale length of vertical electron density gradient would be the reason to cause the seasonal variations of scintillation occurrence, and the equinoctial asymmetry of scintillation occurrence rate over low latitude can be related to the background electron density and the vertical drifts around sunset in F-layer. The correlations between the scintillation strength represented by the daily maximum S4 and the daily maximum values of foF2, hmF2, h’F, Hm, and also the drifts over low latitudes were weak, which need to be further studied.

Seismic Induced Ground Deformation and Ionospheric Perturbations of the 29 July 2021, Mw 8.2 Chignik Earthquake, Alaska

AbstractThe subsurface, surface, and ionospheric characteristics associated with the 29 July 2021 Mw 8.2 Chignik Earthquake are studied in detail using continuous Global Positioning System (cGPS) data over Alaska. The cGPS‐inverted coseismic displacements demonstrate that the slip is distributed along the rupture area northeast of the epicenter with a maximum coseismic slip of ∼3.85 m occurring at a depth of ∼24.25 km. The vertical surface displacement estimated from the coseismic slip exhibits a similar deformation pattern with a maximum uplift of ∼1.0 m over the highly slip area. The ionospheric electron density perturbations associated with the Chignik earthquake were investigated using cGPS‐derived Total Electron Content (TEC) data. Unlike the northeast‐directed coseismic rupture and surface uplift, the ionospheric imprints of this event are more dominant southwest of the epicenter. This study reveals that the Earth's magnetic field and the ionospheric background electron density significantly controlled the TEC perturbation orientation and amplitudes rather than the rupture propagation and coseismic uplift pattern.

(Invited, Digital Presentation) Nondegenerate Hydrogen-Doped Polycrystalline Indium Oxide (InOx:H) Thin Films for High-Mobility Thin Film Transistors

Transparent metal oxide semiconductors (OSs) have been extensively investigated for use as the active channel layer of thin film transistors (TFTs) for next-generation flat-panel displays, nonvolatile memories, image sensors, and pH sensors, to name a few. Among OSs, the amorphous In–Ga–Zn–O (IGZO) has attracted particular attention for TFT applications owing to its high field effect mobility (μFE) of more than 10 cm2V−1s−1, steep subthreshold swing (S.S.), extremely low off-state current, large-area uniformity, and good bias stress stability. Although the μFE of an IGZO TFT is approximately one order of magnitude higher than that of an amorphous Si TFT, further improvement of the μFE of OS TFTs is required to expand their range of applications as an alternative to polycrystalline Si TFT.Single-crystalline In2O3 has a Hall mobility as high as 160 cm2V−1s−1, which makes amorphous (a-) or polycrystalline (poly-) InOx a potential material for enhancing the μFE of OS TFTs. However, undoped InOx thin films is known as a degenerate semiconductor with high background electron density of over 1020 cm-3, which is attributed to the presence of native defects, such as oxygen vacancies, making them unsuitable for a channel material of OS TFTs. In this presentation, nondegenerate hydrogen-doped polycrystalline InOx (poly-InOx:H) thin films were successfully prepared by low-temperature solid phase crystallization (SPC). A degenerate amorphous InOx:H thin film was deposited by sputtering in Ar, O2, and H2 gases, and an amorphous to polycrystalline phase transition (SPC) of the film was achieved after PDA at more than 175 °C. By PDA at 250 °C in air, a nondegenerate poly-InOx:H film could be obtained with a carrier density as low as 2.4 × 1017 cm−3, which is approximately three orders of magnitude lower than that of the initial a-InOx:H film. The TFTs with a 50 nm thick nondegenerate poly-InOx:H channel could be fully depleted by a gate electric field. A maximum μFE of 125.7 cm2V−1s−1 was exhibited by the TFT with the poly-InOx:H channel. The use of a nondegenerate poly-InOx:H film is a promising approach to boost the μFE of OS TFTs.

High-Frequency Channel Modeling Based on the Multi-Source Ionospheric Assimilation Model

In this paper, we explored how to more accurately predict the quality of high-frequency links and how to better research and improve the capabilities of high-frequency communication, reconnaissance, and positioning systems. Based on the background electron density generated by the ionospheric assimilation model and 3D ray-tracing technology, more realistic and accurate high-frequency channel parameters with physical meanings were obtained. On this basis, a complete high-frequency channel model that can be used for simulation and prediction was constructed. First, the ionospheric assimilation model, the high-frequency channel model, and the method used for calculating the parameters of the high-frequency channel model based on the background electron density generated by the multi-source ionospheric assimilation model are introduced. Then, the HF oblique sounding experiment and experimental data processing are introduced. Finally, the modeling and simulation of the high-frequency channel are compared with the HF oblique sounding experimental results. The simulation results showed that the modeling results of the high-frequency channel based on the multi-source ionospheric assimilation model proposed in this paper were similar to the HF oblique sounding experimental results. The average deviation of the difference between the simulation results and the experimental ones of the group path, the group path broadening, and the Doppler frequency shift are 29.2200 km, 17.3456 km, and 0.2121 Hz, respectively. The group delay, Doppler frequency shift, and delay broadening results calculated by the high-frequency channel model simulation were relatively accurate and could be used in high-frequency channel quality reporting and prediction, high-frequency reconnaissance and geolocation, and high-frequency radar frequency selection and positioning, etc.

Equatorial plasma bubbles for solar maximum & moderate year of the solar cycle 24

The fluctuations in the electron density of the F-region in the ionosphere as compared to the background electron density are the sign of plasma irregularities which is a well-known phenomenon. They occur during post-sunset hours and degrade ionospheric radio wave communication majorly the navigation signals. To explore the features of equatorial plasma bubbles (EPBs) over the Indian region throughout the solar maximum year 2014 and the solar moderate year 2017, we have examined day and night hours plasma irregularities from Defense Meteorological Satellite Program (DMSP) with spacecraft as F15 with total crossings as 9698. From the total crossings, 1115 crossings were obtained with EPBs degrading the communication and navigation signals. The distribution of EPBs was studied monthly, seasonally, and longitudinally for the solar maximum and moderate years which has given significant results. We have also analyzed the occurrence of EPBs during the geomagnetic storms with Disturbed storm time index (Dst) ≤ -100 nT occurred in the solar maximum and moderate years. We have observed that the regular occurrence of EPBs was there during the initial and main phase but smoothens up in course of the recovery phases of the storm. These results are discussed with those of earlier results and are in good agreement too. The observed inferences will help to improve the telecommunication sector in the Indian region.

Distinct ionospheric response to three different geomagnetic storms during 2016 using GPS-TEC observations over the Indian equatorial and low latitude sectors

The ionospheric response during three distinct geomagnetic storms occurred in the year 2016 is investigated using GPS-TEC observations in the Indian equatorial and low latitude sectors. The three geomagnetic storms are considered for this study which were occurred on 20 January 2016 (2230 LT), 6 March 2016 (0230 LT) and 13 October 2016 (0530 LT) with minimum Sym-H values of −95 nT, −110 nT and −114 nT respectively. These three geomagnetic storms are different from one another in the sustainment of main and recovery phases and are occurred at three different local times corresponding to the Indian longitudes. This study brings out the major differences of these three geomagnetic storms characteristics and their distinct effects on the equatorial and low latitude ionosphere. Significant changes in the VTEC during main and recovery phases of these three storms are found to be mainly associated with prompt penetration electric fields and thermospheric neutral compositional changes. During the storm of 20 January 2016, positive storm effects during main and recovery phases of the storm are in association with the penetration electric fields. The complete main phase for the 6 March 2016 geomagnetic storm was occurred during night time and no changes in VTEC has been identified, which could be due to the weak background electron density. A positive storm effect is noticed during the recovery phases of the storms of 6 March 2016 and 13 October 2016, due to the storm induced electric fields differences and in particular due to the enhanced [O]/[N2] ratio in thermospheric composition. A strong positive storm effect caused by Co-rotating Interacting Region (CIR) induced disturbances after the 13 October 2016 storm is also discussed.

On the North‐South Asymmetry of Co‐Seismic Ionospheric Disturbances During the 16 September 2015 Illapel M8.3 Earthquake

AbstractThe Mw8.3 Illapel earthquake on 16 September 2015 induced ionospheric disturbances detected by Global Positioning System ground‐based total electron content (TEC) observations, which display much stronger TEC perturbations above the northern region of the epicenter than above the southern region. To investigate the cause of the asymmetry, we extend the Wave Perturbation—Global Ionosphere‐Thermosphere Model from using a point source representing the epicentral crustal movement to using an extended source including the ground motion caused by propagating seismic waves. The modeling results reveal that on average, 31% of the north‐south asymmetry in the TEC perturbation magnitude is caused by the different ground motion strengths northward and southward of the epicenter, while the remaining 69% is attributed to the background ionospheric state including the magnetic field. In particular, the spatial variation of the background electron density and the magnetic field inclination angle contributes comparably to the north‐south asymmetry.

Periodical discharge regime transitions under long-term repetitive nanosecond pulses

Intuitively, the nanosecond repetitively pulsed (NRP) corona and spark regimes are sustained successively after onsets due to the high background electron density and/or the surplus heat. In this paper, the NRP discharge unexpectedly swings among different regimes (corona → glow → spark → corona → …) in one pulse train, which is characterized by the periodical spark quench and reestablishment. We have investigated discharge regime instabilities by applying long-term repetitive high-voltage nanosecond pulses of ∼15 ns duration to needle–needle and needle–plane gaps in atmospheric-pressure N2 and N2–O2 mixtures. Pulse-sequence resolved electrical and optical diagnostics have been implemented to capture transition processes. The initial corona gradually grows into glow and then spark ‘pulse-by-pulse’, however, the spark regime was interrupted after a certain number of voltage pulses until the next reestablishment. Narrow pulse width impedes the discharge instability growth within one pulse, and a certain number of voltage pulses are required for the discharge regime transition. The addition of O2 dramatically boosts the duration length of spark regime. A lower output impedance of the power supply induces a higher deposited energy into a spark, however, not necessarily leads to a longer spark regime duration, although both the energy storage and the average electric field strength are approximate. Polarity effects, conventionally diminished in pulse-periodic discharges, are still evident during the discharge regime transition. The periodical discharge regime transition is qualitatively explained based on the plasma–source coupling and the evolution trajectory along the power transfer curve. Feedback mechanisms and residual-conductivity related screening effect in NRP spark discharges are analyzed based on a simplified 0D simulation. The periodical feature is probably caused by the insufficient average deposited energy per unit distance per one pulse cycle. In-depth understandings of ‘non-binary’ regimes (neither corona nor spark) and memory effect mechanisms of NRP discharges could be reached.

Heavy metals in the atmosphere determination by double-pulse laser induced breakdown spectroscopy

In this paper, the double-pulse laser-induced breakdown spectroscopy (DP-LIBS) technique was used to analyze the heavy metal samples collected in the atmosphere using an air sampler. The enhancement characteristics of the plasma spectra were studied by using different laser wavelength combinations with 1064, 532, and 355 nm Nd:YAG lasers. The plasma spectrum of the sample was greatly enhanced when the combined laser wavelengths were 355 and 1064 nm. On this basis, the optimal inter-pulse delay time is obtained to get the maximum plasma spectrum. The relationship of the signal to background ratio, electron temperature, and electron density of the plasma spectrum with inter-pulse delay and acquisition delay is also discussed. Finally, the optimal pulse delay and acquisition time were obtained. DP-LIBS technology can effectively improve the detection effect of heavy metals in the atmosphere, which is a very promising tool in the field of environmental monitoring.

A Tomographic Method for the Reconstruction of the Plasmasphere Based on COSMIC/ FORMOSAT-3 Data

A tomographic method has been developed for reconstructing the topside ionospheric and plasmaspheric electron density distribution using total electron content (TEC) measurements from global positioning system (GPS) receivers aboard the constellation observing system for meteorology, ionosphere, and climate&#x002F;Formosa Satellite Mission 3 (COSMIC&#x002F;FORMOSAT-3). Since the COSMIC&#x002F;FORMOSAT-3 constellation has an orbit altitude of about 800 km, the integral TEC measurements obtained from the topside GPS navigation data are rather small and imposed relevant challenges to obtaining stable electron density reconstructions. However, the developed method can represent the natural variability of the plasma ambient in terms of latitude, altitude, solar activity, season, and local time when analyzing electron density reconstructions during 2008&#x2013;2013. The method employs independent spatial grids for satellite rising and setting geometries and imposes a set of constraints to stabilize the solution in the presence of noise and ill-conditioned geometry. We further consider background ionosphere and plasmasphere models for electron density initialization and filling data gaps. The quality assessment using TEC and <i>in-situ</i> electron density measurements has shown that the proposed method performs better than the background model, with improvements of about 26&#x0025; in TEC and 20&#x0025; in terms of electron density. Our investigation also reveals the necessity of more accurate background electron density representations and precise TEC measurements in order to have better plasmaspheric specifications at high altitudes.