Bibliography

Signatures of Equatorial Plasma Bubbles and Ionospheric Scintillations from Magnetometer and GNSS Observations in the Indian Longitudes during the Space Weather Events of Early September 2017

Scintillation due to ionospheric plasma irregularities remains a challenging task for the space science community as it can severely threaten the dynamic systems relying on space-based navigation services. In the present paper, we probe the ionospheric current and plasma irregularity characteristics from a latitudinal arrangement of magnetometers and Global Navigation Satellite System (GNSS) stations from the equator to the far low latitude location over the Indian longitudes, during the severe space weather events of 6–10 September 2017 that are associated with the strongest and consecutive solar flares in the 24th solar cycle. The night-time influence of partial ring current signatures in ASYH and the daytime influence of the disturbances in the ionospheric E region electric currents (Diono) are highlighted during the event. The total electron content (TEC) from the latitudinal GNSS observables indicate a perturbed equatorial ionization anomaly (EIA) condition on 7 September, due to a sequence of M-class solar flares and associated prompt penetration electric fields (PPEFs), whereas the suppressed EIA on 8 September with an inverted equatorial electrojet (EEJ) suggests the driving disturbance dynamo electric current (Ddyn) corresponding to disturbance dynamo electric fields (DDEFs) penetration in the E region and additional contributions from the plausible storm-time compositional changes (O/N2) in the F-region. The concurrent analysis of the Diono and EEJ strengths help in identifying the pre-reversal effect (PRE) condition to seed the development of equatorial plasma bubbles (EPBs) during the local evening sector on the storm day. The severity of ionospheric irregularities at different latitudes is revealed from the occurrence rate of the rate of change of TEC index (ROTI) variations. Further, the investigations of the hourly maximum absolute error (MAE) and root mean square error (RMSE) of ROTI from the reference quiet days’ levels and the timestamps of ROTI peak magnitudes substantiate the severity, latitudinal time lag in the peak of irregularity, and poleward expansion of EPBs and associated scintillations. The key findings from this study strengthen the understanding of evolution and the drifting characteristics of plasma irregularities over the Indian low latitudes.

Vankadara, Ram; Panda, Sampad; Amory-Mazaudier, Christine; Fleury, Rolland; Devanaboyina, Venkata; Pant, Tarun; Jamjareegulgarn, Punyawi; Haq, Mohd; Okoh, Daniel; Seemala, Gopi;

Published by: Remote Sensing      Published on: jan

YEAR: 2022     DOI: 10.3390/rs14030652

space weather; equatorial plasma bubbles; ionospheric irregularity; global navigation satellite system; magnetometer; poleward drift; rate of change of TEC index; scintillations; storm-time electric currents

Bayesian approach for auroral oval reconstruction from ground-based observations

Naked eye observations of aurorae might be used to obtain information on the large-scale magnetic field of the Earth at historic times. Their abundance may also help bridge gaps in observational time-series of proxies for solar activity such as the sunspot number or cosmogenic isotopes. With information derived from aurora observations like observing site, time of aurora sighting and position on the sky we can reconstruct the auroral oval. Since aurorae are correlated with geomagnetic indices like the Kp index, it is possible to obtain information about the terrestrial magnetic field in the form of the position of the magnetic poles as well as the magnetic disturbance level. Here we present a Bayesian approach to reconstruct the auroral oval from ground-based observations by using two different auroral oval models. With this method we can estimate the position of the magnetic poles in corrected geomagnetic coordinates as well as the Kp index. The method is first validated on synthetic observations before it is applied to four modern geomagnetic storms between 2003 and 2017 where ground-based reports and photographs were used to obtain the necessary information. Based on the four modern geomagnetic storms we have shown, that we are able to reconstruct the pole location with an average accuracy of ≈2° in latitude and ≈11° in longitude. The Kp index can be inferred with a precision of one class. The future goal is to employ the method to historical storms, where we expect somewhat higher uncertainties, since observations may be less accurate or not favorably distributed.

Wagner, D.; Neuhäuser, R.; Arlt, R.;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on: feb

YEAR: 2022     DOI: 10.1016/j.jastp.2022.105824

auroral oval; Magnetic storms; space weather

Features of the Ionospheric Storm on December 21--24, 2016

The purpose of this work is to investigate the response of the F region and topside ionosphere to the moderate geomagnetic storm on December 21, 2016 (Kp max = 6). The subject of the study is the height–time variations in the parameters of the ionospheric plasma over Kharkiv. Experimental data were obtained using vertical sounding and incoherent scatter methods by the ionosonde and incoherent scatter radar. The presented results are based on the correlation analysis of the incoherent scattered signal. The ion and electron temperatures, as well as the ionospheric plasma velocity, were determined from a set of measured correlation functions of the incoherently scattered signal. The electron density was calculated using the following parameters measured for a number of ionospheric heights: power of the incoherent scatter signal, ion and electron temperatures, and the electron density at the ionospheric F2 layer peak, which is calculated from the critical frequency measured by the ionosonde. The moderate geomagnetic storm was accompanied by an ionospheric storm over Kharkiv with sign-variable phases (first positive and second negative). The peak increase in the electron density was 1.8 times and decrease was 3.4 times. The negative phase was accompanied by a slight rise of the F2 layer (by 20–28 km), which could be due to a decrease in the vertical component of the plasma velocity and an increase in the electron temperature by 600–800 K and ion temperature by 100–160 K. Effects of strong negative ionospheric disturbances were registered during the subsequent magnetospheric disturbance of December 22–24, 2016, with a decrease in electron density at the F2 layer peak up to 2.5–4.9 times. The effects of negative disturbances manifested themselves in the variations of temperatures of electrons and ions. In general, the moderate magnetic storm caused significant changes in the electron density in the ionospheric F2 layer peak, which were accompanied by heating of the ionospheric plasma as well as changes in variations of the vertical component of the ionospheric plasma velocity and the height of ionization during the main phase of the magnetic storm.

Katsko, S.; Emelyanov, Ya.; Chernogor, L.;

Published by: Kinematics and Physics of Celestial Bodies      Published on: mar

YEAR: 2021     DOI: 10.3103/S0884591321020045

geomagnetic storm; Electron density; Ionospheric storm; space weather; ionosonde; electron and ion temperatures; incoherent scatter radar; plasma velocity; positive and negative storm phases

Spread-F occurrence during geomagnetic storms near the southern crest of the EIA in Argentina

This work presents, for the first time, the analysis of the occurrence of ionospheric irregularities during geomagnetic storms at Tucumán, Argentina, a low latitude station in the Southern American longitudinal sector (26.9°S, 294.6°E; magnetic latitude 15.5°S) near the southern crest of the equatorial ionization anomaly (EIA). Three geomagnetic storms occurred on May 27, 2017 (a month of low occurrence rates of spread-F), October 12, 2016 (a month of transition from low to high occurrence rates of spread-F) and November 7, 2017 (a month of high occurrence rates of spread-F) are analyzed using Global Positioning System (GPS) receivers and ionosondes. The rate of change of total electron content (TEC) Index (ROTI), GPS Ionospheric L-band scintillation, the virtual height of the F-layer bottom side (h F) and the critical frequency of the F2 layer (foF2) are considered. Furthermore, each ionogram is manually examined for the presence of spread-F signatures. The results show that, for the three events studied, geomagnetic activity creates favorable conditions for the initiation of ionospheric irregularities, manifested by ionogram spread-F and TEC fluctuation. Post-midnight irregularities may have occurred due to the presence of eastward disturbance dynamo electric fields (DDEF). For the May storm, an eastward over-shielding prompt penetration electric field, (PPEF) is also acting. A possibility is that the PPEF is added to the DDEF and produces the uplifting of the F region that helps trigger the irregularities. Finally, during October and November, strong GPS L band scintillation is observed associated with strong range spread-F (SSF), that is, irregularities extending from the bottom-side to the topside of the F region.

González, Gilda;

Published by: Advances in Space Research      Published on: feb

YEAR: 2021     DOI: 10.1016/j.asr.2020.10.051

Geomagnetic storms; ionospheric irregularities; space weather; Spread-F

Evaluating Auroral Forecasts Against Satellite Observations

The aurora is a readily visible phenomenon of interest to many members of the public. However, the aurora and associated phenomena can also significantly impact communications, ground-based infrastructure, and high-altitude radiation exposure. Forecasting the location of the auroral oval is therefore a key component of space weather forecast operations. A version of the OVATION-Prime 2013 auroral precipitation model (Newell et al., 2014, https://doi.org/10.1002/2014sw001056) was used by the UK Met Office Space Weather Operations Centre (MOSWOC). The operational implementation of the OVATION-Prime 2013 model at the UK Met Office delivered a 30-min forecast of the location of the auroral oval and the probability of observing the aurora. Using weather forecast evaluation techniques, we evaluate the ability of the OVATION-Prime 2013 model forecasts to predict the location and probability of the aurora occurring by comparing the forecasts with auroral boundaries determined from data from the IMAGE satellite between 2000 and 2002. Our analysis shows that the operational model performs well at predicting the location of the auroral oval, with a relative operating characteristic (ROC) score of 0.82. The model performance is reduced in the dayside local time sectors (ROC score = 0.59) and during periods of higher geomagnetic activity (ROC score of 0.55 for Kp = 8). As a probabilistic forecast, OVATION-Prime 2013 tends to underpredict the occurrence of aurora by a factor of 1.1–6, while probabilities of over 90\% are overpredicted.

Mooney, M.; Marsh, M.; Forsyth, C.; Sharpe, M.; Hughes, T.; Bingham, S.; Jackson, D.; Rae, I.; Chisham, G.;

Published by: Space Weather      Published on:

YEAR: 2021     DOI: 10.1029/2020SW002688

AURORA; auroral forecasting; forecast verification; OVATION-Prime 2013; ROC scores; space weather

Toward a Next Generation Particle Precipitation Model: Mesoscale Prediction Through Machine Learning (a Case Study and Framework for Progress)

We advance the modeling capability of electron particle precipitation from the magnetosphere to the ionosphere through a new database and use of machine learning (ML) tools to gain utility from those data. We have compiled, curated, analyzed, and made available a new and more capable database of particle precipitation data that includes 51 satellite years of Defense Meteorological Satellite Program (DMSP) observations temporally aligned with solar wind and geomagnetic activity data. The new total electron energy flux particle precipitation nowcast model, a neural network called PrecipNet, takes advantage of increased expressive power afforded by ML approaches to appropriately utilize diverse information from the solar wind and geomagnetic activity and, importantly, their time histories. With a more capable representation of the organizing parameters and the target electron energy flux observations, PrecipNet achieves a \textgreater50\% reduction in errors from a current state-of-the-art model oval variation, assessment, tracking, intensity, and online nowcasting (OVATION Prime), better captures the dynamic changes of the auroral flux, and provides evidence that it can capably reconstruct mesoscale phenomena. We create and apply a new framework for space weather model evaluation that culminates previous guidance from across the solar-terrestrial research community. The research approach and results are representative of the “new frontier” of space weather research at the intersection of traditional and data science-driven discovery and provides a foundation for future efforts.

McGranaghan, Ryan; Ziegler, Jack; Bloch, Téo; Hatch, Spencer; Camporeale, Enrico; Lynch, Kristina; Owens, Mathew; Gjerloev, Jesper; Zhang, Binzheng; Skone, Susan;

Published by: Space Weather      Published on:

YEAR: 2021     DOI: 10.1029/2020SW002684

space weather; magnetosphere-ionosphere coupling; data science; evaluation; machine learning; particle precipitation

Determination of Auroral Electrodynamic Parameters From AMPERE Field-Aligned Current Measurements

We calculate high latitude electrodynamic parameters using global maps of field-aligned currents from the Active Magnetosphere and Planetary Response Experiment (AMPERE). The model is based on previous studies that relate field-aligned currents to auroral Pedersen and Hall conductances measured by incoherent scatter radar. The field-aligned currents and conductances are used to solve for the electric potential at high latitudes from which electric fields are computed. The electric fields are then used with the conductances to calculate horizontal ionospheric currents. We validate the results by simulating the SuperMAG magnetic indices for 30 geomagnetically active days. The correlation coefficients between derived and actual magnetic indices were 0.68, 0.76, and 0.84 for the SMU, SML, and SME indices, respectively. We show examples of times when the simulations differ markedly from the measured indices and attribute them to either small-scale, substorm-related current structures or the effects of neutral winds. Overall, the performance of the model demonstrates that with few exceptions, auroral electrodynamic parameters can be accurately deduced from the global field-aligned current distribution provided by AMPERE.

Robinson, R.; Zanetti, Larry; Anderson, Brian; Vines, Sarah; Gjerloev, Jesper;

Published by: Space Weather      Published on:

YEAR: 2021     DOI: 10.1029/2020SW002677

space weather; auroral currents; auroral electrodynamics; conductivities; electric fields; field-aligned currents

Explicit IMF By-Dependence in Geomagnetic Activity: Quantifying Ionospheric Electrodynamics

Geomagnetic activity is mainly driven by the southward (Bz) component of the interplanetary magnetic field (IMF), which dominates all solar wind coupling functions. Coupling functions also depend on the absolute value of the dawn-dusk (By) component of the IMF, but not on its sign. However, recent studies have shown that for a fixed level of solar wind driving, auroral electrojets in the Northern Hemisphere (NH) are stronger for By \textgreater 0 than for By \textless 0 during NH winter. In NH summer, the dependence on the By sign is reversed. While this By sign dependence, also called the explicit By-dependence, is very strong in the winter hemisphere, it is weak in the summer hemisphere. Moreover, the explicit By-dependence is much stronger in the westward electrojet than in the eastward electrojet. In this study, we study how the explicit IMF By-dependence is coupled with large-scale field-aligned currents (FACs) by using FAC measurements from the Active Magnetosphere and Planetary Electrodynamics Response Experiment and an empirical ionospheric conductance model. We model the complete ionospheric electrodynamics by solving the current continuity equation, and show that during periods of elevated solar wind driving (Bz \textless 0), the IMF By component modulates Regions 1 and 2 FACs in the dawn sector of the winter hemisphere. This leads to an explicit By-dependence in ionospheric conductance and the westward electrojet. We also show that the By-dependence of FACs and conductance is weak in the dusk sector, which explains the earlier observation of the weak By-dependence of the eastward electrojet.

Holappa, L.; Robinson, R.; Pulkkinen, A.; Asikainen, T.; Mursula, K.;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2021JA029202

space weather; magnetosphere-ionosphere coupling; field-aligned currents; geomagnetic activity

Geomagnetic Pulsations Driving Geomagnetically Induced Currents

Geomagnetically induced currents (GICs) are driven by the geoelectric field induced by fluctuations of Earth s magnetic field. Drivers of intense GICs are often associated with large impulsive events such as coronal mass ejections. To a lesser extent fluctuations from regular oscillations of the geomagnetic field, or geomagnetic pulsations, have also been identified as possible drivers of GICs. In this work we show that these low-frequency pulsations are directly observed in measured GIC data from power networks. Due to the low-pass nature of GICs, Pc5 and lower-frequency pulsations drive significant GICs for an extended duration even at midlatitudes. Longer-period Ps6-type disturbances apparently not typical of midlatitudes are seen with GIC amplitudes comparable to the peak GIC at storm sudden commencement. The quasi-ac (alternating current) nature of the sustained pulsation driving affects the power system response and cannot be properly modeled using only direct current (dc) models. A further consideration is that the often used dB/dt GIC proxy is biased to the sampling rate of the geomagnetic field measurements used. The dB/dt metric does not adequately characterize GIC activity at frequencies in the low ultralow-frequency (ULF) range, and a frequency-weighted proxy akin to geoelectric field should be used instead.

Heyns, M.; Lotz, S.; Gaunt, C.;

Published by: Space Weather      Published on:

YEAR: 2021     DOI: 10.1029/2020SW002557

space weather; geomagnetic pulsations; geomagnetically induced currents

PROBA2 LYRA Occultations: Thermospheric Temperature and Composition, Sensitivity to EUV Forcing, and Comparisons With Mars

A method for retrieving temperature and composition from 150 to 350 km in Earth s thermosphere using total number density measurements made via extreme ultraviolet (EUV) solar occultations by the Project for OnBoard Autonomy 2/Large Yield Radiometer (PROBA2/LYRA) instrument is presented. Systematic and random uncertainties are calculated and found to be less than 5\% for the temperature measurements and 5\%–20\% for the composition measurements. Regression coefficients relating both temperature and the [O]/[N2] abundance ratio with EUV irradiance at 150, 275, and 350 km are reported. Additionally, it is shown that the altitude where [O] equals [N2] decreases with increasing solar EUV irradiance, an effect attributed to thermal expansion. Temperatures from 2010 to 2017 are compared with estimates from the MSIS empirical model and show good agreement at the dawn terminator but LYRA is markedly cooler at the dusk terminator, with the MSIS-LYRA temperature difference increasing with solar activity. Anthropogenic cooling can explain this discrepancy at periods of lower solar activity, but the divergence of temperature with increasing solar activity remains unexplained. LYRA measurements of the exospheric temperature sensitivity to EUV irradiance are compared with contemporaneous measurements made at Mars, showing that the exospheric temperature at Mars is approximately half as sensitive to EUV variability as that of Earth.

Thiemann, Edward; Dominique, Marie;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2021JA029262

comparative planetology; EUV; occultations; space weather; thermosphere

First Look at a Geomagnetic Storm With Santa Maria Digisonde Data: F Region Responses and Comparisons Over the American Sector

Santa Maria Digisonde data are used for the first time to investigate the F region behavior during a geomagnetic storm. The August 25, 2018 storm is considered complex due to the incidence of two Interplanetary Coronal Mass Ejections and a High-Speed Solar Wind Stream (HSS). The F 2 layer critical frequency (f o F 2) and its peak height (h m F 2) collected over Santa Maria, near the center of the South American Magnetic Anomaly (SAMA), are compared with data collected from Digisondes installed in the Northern (NH) and Southern (SH) Hemispheres in the American sector. The deviation of f o F 2 (Df o F 2) and h m F 2 (Dh m F 2) are used to quantify the ionospheric storm effects. Different F region responses were observed during the main phase (August 25–26), which is attributed to the traveling ionospheric disturbances and disturbed eastward electric field during nighttime. The F region responses became highly asymmetric between the NH and SH at the early recovery phase (RP, August 26) due to a combination of physical mechanisms. The observed asymmetries are interpreted as caused by modifications in the thermospheric composition and a rapid electrodynamic mechanism. The persistent enhanced thermospheric [O]/[N2] ratio observed from August 27 to 29 combined with the increased solar wind speed induced by the HSS and IMF B z fluctuations seem to be effective in causing the positive ionospheric storm effects and the shift of the Equatorial Ionization Anomaly crest to higher than typical latitudes. Consequently, the most dramatic positive ionospheric storm during the RP occurred over Santa Maria (∼120\%).

Moro, J.; Xu, J.; Denardini, C.; Resende, L.; Neto, P.; Da Silva, L.; Silva, R.; Chen, S.; Picanço, G.; Carmo, C.; Liu, Z.; Yan, C.; Wang, C.; Schuch, N.;

Published by: Journal of Geophysical Research: Space Physics      Published on:

YEAR: 2021     DOI: 10.1029/2020JA028663

Digisonde; Equatorial ionization anomaly; F-region; Ionospheric storm; SAMA; space weather

The international reference ionosphere--status 2013

This paper describes the latest version of the International Reference Ionosphere (IRI) model. IRI-2012 includes new models for the electron density and ion densities in the region below the F-peak, a storm-time model for the auroral E-region, an improved electron temperature model that includes variations with solar activity, and for the first time a description of auroral boundaries. In addition, the thermosphere model required for baseline neutral densities and temperatures was upgraded from MSIS-86 to the newer NRLMSIS-00 model and Corrected Geomagnetic coordinates (CGM) were included in IRI as an additional coordinate system for a better representation of auroral and polar latitudes. Ongoing IRI activities towards the inclusion of an improved model for the F2 peak height hmF2 are discussed as are efforts to develop a \textquotedblleftReal-Time IRI\textquotedblright. The paper is based on an IRI status report presented at the 2013 IRI Workshop in Olsztyn, Poland. The IRI homepage is at\ IRImodel.org.

Bilitza, Dieter;

Published by: Advances in Space Research      Published on: 04/2015

YEAR: 2015     DOI: 10.1016/j.asr.2014.07.032

Forecast; Ionosphere; IRI; Real-Time; space weather

Is Space Weather Different Over Africa, and If So, Why? An AGU Chapman Conference Report

With the increasing reliance on technology, the impact of space weather on engineered systems will certainly increase unless suitable protective measures are taken. Understanding the physics behind space weather impacts and improving the forecasting are the major objectives of the space science community. It is well recognized that many space weather impacts, especially on communications systems, arise from structures in the ionosphere. The equatorial ionosphere, in particular, is one of the most complex and is host to numerous instabilities and interactions, with many unresolved questions regarding its dynamics and variability. Radio waves, either transmitted through the ionosphere, for satellite communication and navigation, or reflected off the ionosphere for HF and radar applications, are all impacted by ionospheric variability and structure. Ionospheric irregularities or plasma \textquotedblleftbubbles\textquotedblright occurring at low latitudes are one such source of interference. These irregularities cause scintillations on satellite radio transmissions, resulting in information loss in communications, as well as degradation in positioning and navigation used in aviation and maritime industries.

Yizengaw, Endawoke; Doherty, Patricia; Fuller-Rowell, Tim;

Published by: Space Weather      Published on: 07/2013

YEAR: 2013     DOI: 10.1002/swe.20063

atmosphere ionosphere interactions; ionospheric irregularities; space weather

Design of FUV imaging spectrometer based on crossed Czerny-Turner structure

This article describes the characteristics of the far ultraviolet (FUV) radiation and its applications in the space weather s research and prediction. The FUV imaging spectrometer is irreplaceable to get the FUV radiation data of the earth s upper atmosphere. Some key technologies of FUV spectrometer are analyzed respectively, including window materials, FUV light source, FUV detectors and FUV coating, which offer theoretical foundation for FUV imaging spectrometer. The paper presents a FUV band imaging spectrometer s optical system which is based on crossed Czerny-Turner structure with all reflective components in it. The wavelength range of the FUV spectrometer optical system is from 100nm to 200nm and the initial structure is simulated and optimized by Zemax in order to improve the spectral resolution. The theoretical spectral resolution of the system is better than 1nm, and it has a certain imaging capacity.

Wu, Yan; Tang, Yi; Ni, Guoqiang; Sheng, Yunlong; Wang, Yongtian; Zeng, Lijiang;

Published by:       Published on:

YEAR: 2009     DOI: 10.1117/12.806967

space weather; far ultraviolet; Imaging spectrometer; crossed Czerny-Turner system; optical design

Contributions of imaging Echelle spectrographs to daytime optical aeronomy

We present a brief overview of the contributions made by high spectral resolution imaging spectrographs that are capable of obtaining daytime airglow and auroral emissions in the presence of scattered solar background continuum, to the advancement in our understanding of the dynamics in daytime upper atmosphere. By making use of ground-based OI 6300 angstrom daytime emissions from various geomagnetic latitudes this technique has succeeded in demonstrating many interesting and first of their kind results ranging from ionosphere–thermosphere coupling, space weather interactions to magnetosphere–thermosphere–ionosphere coupling. Finally, in view of the promising results by this technique we propose future advancements in both instrumentation and strategic observational planning with optical spectrographs.

Pallamraju, D.; Chakrabarti, S.;

Published by: Journal of Atmospheric and Solar-Terrestrial Physics      Published on:

YEAR: 2006     DOI: https://doi.org/10.1016/j.jastp.2005.05.013

dayglow; AURORA; Spectroscopy; Optical techniques; Thermosphere–ionosphere coupling; space weather

Compact FUV camera concept for space weather applications

Far ultraviolet (FUV) images of Earth from space have proven invaluable in revealing contextual phenomena associated with space weather in the high latitude auroral regions and in the mid and equatorial regions. Images of this nature can be used to investigate compelling questions associated with the interaction of the ionosphere/mesosphere-magnetosphere-solar wind. Observations using images that lead to quantitative analyses are required to significantly advance the state of knowledge with regard to the affects of space weather and the interaction between and within these regions of Geospace. Current available image data sets are sufficient for qualitative analysis and morphological investigations, and while quantitative analyses are possible, they are difficult and limited to few events at best^1,2. In order to qualitatively access the time, spatial, and causal phenomena on global scales, simultaneous images of various FUV emissions with a combination of better spatial, temporal and spectral resolution and sensitivity than currently available are required. We present an instrument concept that is being developed to improve the spatial, temporal and spectral resolution and sensitivity needed to perform the quantitative analysis that enable significant advancement in our understanding of the impact of space weather on Geospace. The approach is to use the "self-filtering" concept³ that combines the imaging and filtering functions and thus reduces the size of the 4-mirror off-axis optical system. The optical and filter design will de described.

Spann, James; Fineschi, Silvano; Viereck, Rodney;

Published by:       Published on:

YEAR: 2005     DOI: 10.1117/12.615201

Camera; Filters; far ultraviolet; space weather; MI coupling; Ionosphere; AURORA; Geospace