We review the morphology and dynamics of electrical current systems terrestrial magnetosphere ionosphere. Observations from Active Magnetosphere Planetary Electrodynamics Response Experiment (AMPERE) over three years 2010 to 2012 are employed illustrate variability field-aligned currents that couple ionosphere, on timescales minutes years, in response impact solar wind disturbances changes level illumination polar ionospheres. The is discussed within context occurrence magnetic reconnection...

Abstract. It has recently been proposed that ripples inherent to the bow shock during radial interplanetary magnetic field (IMF) may produce local high speed flows in magnetosheath. These jets can have a dynamic pressure much larger than of solar wind. On 17 March 2007, several this type were observed by Cluster spacecraft. We study detail these and their effects on magnetopause, magnetosphere, ionospheric convection. find (1) could scale size up few RE but less ~6 transverse XGSE axis; (2)...

We present Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations a “Spontaneous Hot Flow Anomaly” (SHFA) upstream from the prenoon bow shock at 0431 UT on 12 August 2007. Although SHFA exhibited greatly heated deflected solar wind plasmas used to identify hot flow anomalies (HFAs), it did not result standard mechanism invoked for formation HFAs, namely interaction an interplanetary magnetic field (IMF) discontinuity with shock. employ THEMIS A, B, C, D...

Abstract We examine the relationship of convection electric fields to formation a polar cap tongue ionization (TOI) from midlatitude plumes storm enhanced density (SED). Observations geomagnetic on 26–27 September 2011 are presented for two distinct SED events. During an hour‐long period activity driven by coronal mass ejection, channel high‐density F region plasma was transported dayside subauroral ionosphere and into extending middle latitudes. This TOI feature associated with HF...

Abstract The polar ionosphere is often characterized by irregularities and fluctuations in the plasma density. We present a statistical study of ionospheric based on observations from European Space Agency's Swarm mission. situ electron density obtained with Langmuir probe total content onboard global positioning system receiver are used to detect irregularities. derive irregularity parameters terms rate change index gradients. also use as parameter data. background closely controlled...

The region 1 (R1) and 2 current systems typically form concentric rings of field‐aligned currents in the polar ionospheres; we term inner ring R1 oval. We apply an automated fitting scheme to densities provided by Active Magnetosphere Planetary Electrodynamics Response Experiment (AMPERE) identify latitude maximum at all magnetic local times yield size investigate dynamics oval response geomagnetic activity for two cases corresponding to: repeated substorm activations with a minimally...

We report observations from the THEMIS spacecraft characterizing nature and importance of low frequency electromagnetic fluctuations on kinetic scales embedded within fast flows in Earth's plasma sheet. A consideration wave property variations with flow speed suggest that for frame frequencies satisfying | v f |/ñ i ≤ ù sc 100| (or 0.2 ≲ 20 Hz) these can generally be described as Alfvén waves. Here is speed, ñ ion gyroradius, are angular cyclical respectively frame. The statistics energy...

High-resolution in situ measurements from the three Swarm spacecraft, a string-of-pearls configuration, provide new insights about combined role of flow channel events and particle impact ionization creating $\textit{F}$ region electron density structures northern Scandinavian dayside cusp. We present case polar cap patch formation where reconnection-driven low-density relative westward is eroding solar-ionized plasma but cusp dominates initial structuring. In cusp, features are observed...

We present unique coordinated observations of the dayside auroral oval, polar cap, and nightside oval by three all-sky imagers, two Super Dual Auroral Radar Network (SuperDARN) radars, Defense Meteorological Satellite Program (DMSP)-17. This data set revealed that a poleward moving form (PMAF) evolved into cap airglow patch propagated across then boundary intensifications (PBIs). SuperDARN detected fast antisunward flows associated with PMAF, DMSP satellite, whose conjunction occurred within...

In this paper we study how GPS, GLONASS, and Galileo navigation signals are compromised by strong irregularities causing severe phase scintillation ($\mathit{\sigma }_{\phi }$ > 1) in the nightside high-latitude ionosphere during a substorm on 3 November 2013. Substorm onset later intensification coincided with polar cap patches entering auroral oval to become blobs. Using Global Navigation Satellite Systems (GNSS) receivers optical data, show driven intense emissions line of sight between...

Abstract Based on their salient features we manually label 5,824 images from various Time History of Events and Macroscale Interactions during Substorms (THEMIS) all‐sky imagers; the labels use are clear/no aurora , cloudy moon arc diffuse discrete . We then a pretrained deep neural network to automatically extract 1,001‐dimensional feature vector these images. Together, vectors used train ridge classifier that is able correctly predict category unseen auroral based extracted with 82%...

Abstract The Swarm satellites offer an unprecedented opportunity for improving our knowledge about polar cap patches, which are regarded as the main space weather issue in caps. We present a new robust algorithm that automatically detects patches using situ plasma density data from Swarm. For both hemispheres, we compute spatial and seasonal distributions of identified separately by A B between December 2013 August 2016. show clear dependency patch occurrence. In Northern Hemisphere (NH),...

Abstract This study surveys space weather effects on GNSS (Global Navigation Satellite System) signals in the nighttime auroral and polar cap ionosphere using scintillation receivers, all‐sky imagers, European Incoherent Scatter Svalbard radar. We differentiate between two types of blobs: blob type 1 (BT 1) which is formed when islands high‐density F region plasma (polar patches) enter nightside oval, 2 2) are generated locally oval by intense particle precipitation. For BT blobs we have...

Abstract In this study, we present global climatological distributions of ionospheric plasma irregularities based on measurements by the Swarm satellites. These first statistics obtained direct, in situ variations with confirm presence three main regions strong irregularities: magnetic equator extending from postsunset to early morning, auroral ovals (from dayside cusp nightside), and inside polar caps. At equatorial latitudes, form two bands enhanced fluctuations centered around ±10°...

We present simultaneous measurements of flow velocities inside a subauroral polarization stream (SAPS) made by six midlatitude high‐frequency SuperDARN radars. The instantaneous observations cover three hours universal time and magnetic local (MLT). From velocity variations across the field‐of‐view radars we infer 2D direction at different longitudes. find that SAPS channel is remarkably constant over course event. speed, however, shows significant temporal spatial variations. After...

We use current density data from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) to identify location of maximum region 1 at all magnetic local times (MLTs). term this R1 oval. Comparing oval with particle precipitation boundaries identified in DMSP data, we find that is located on average within 1° signatures associated open/closed field line boundary (OCB) across dayside nightside MLTs. hence conclude can be used as a proxy for OCB. Studying amount flux...

[1] We identified 1875 wave events in magnetic field data from geosynchronous orbit. Most of these were transverse with respect to the background field, left-hand polarized, and observed post-noon local time sector at frequencies just below helium gyrofrequency. Combined, observations strongly suggest that most are Electromagnetic Ion Cyclotron (EMIC) waves. Average amplitudes presented, binned by frequency, geomagnetic activity time. The amplitude increases increasing activity; increased...

Abstract In this paper we present the first large‐scale statistical study of influence magnetic reconnection on magnitude regions 1 and 2 Birkeland field‐aligned currents (FACs). While previous studies have employed single spacecraft measurements to construct a picture location density currents, it has hitherto been difficult compare in situ solar wind with instantaneous global current measurements. To that end, utilize Active Magnetosphere Planetary Electrodynamics Response Experiment...

[1] The region 1 (R1) and 2 current systems typically form concentric rings of field-aligned currents in the polar ionospheres; we term inner ring R1 oval. We apply an automated fitting scheme to densities provided by Active Magnetosphere Planetary Electrodynamics Response Experiment (AMPERE) identify latitude maximum at all magnetic local times yield size investigate dynamics oval response geomagnetic activity for two cases corresponding to: repeated substorm activations with a minimally...

Abstract We use an automated procedure to identify periods of enhanced dayside reconnection followed by nightside in measurements the polar cap size Active Magnetosphere and Planetary Electrodynamics Response Experiment between January 2010 December 2012; we find 490 such events. investigate dynamics spatial distributions total electron content (TEC) phase scintillations Global Positioning System (GPS) signals across northern region here report three important findings: (1) While a TEC...

Abstract We perform a superposed epoch analysis of the evolution Birkeland currents (field‐aligned currents) observed by Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) during substorms. The study is composed 2900 substorms provided SuperMAG experiment. find that current ovals expand contract over course substorm cycle increase in magnitude approaching onset are further enhanced expansion phase. Subsequently, we categorize their latitude, proxy for amount open...

We reduce measurements made by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) to give total Birkeland (field-aligned) current flowing in both hemispheres monthly hourly bins. analyze these totals using 6 years of data (2010-2015) examine solar zenith angle-driven variations hemispheres, simultaneously, for first time. A diurnal variation is identified flowing, consistent with angle. seasonal also identified, more Northern (Southern) Hemisphere during...

Abstract Ionospheric plasma irregularities can be successfully studied with the Swarm satellites. Parameters derived from in‐situ measurements and topside ionosphere total electron content provide a comprehensive dataset for characterizing structuring along orbits of The Plasma IRregularities (IPIR) data product summarizes these parameters allows systematic studies ionospheric irregularities. IPIR has already been used in investigations variability plasma. This report provides detailed...

Abstract In this paper, the internal structuring of Polarization Jet (PJ)/Subauroral Ion Drift (SAID) is studied. It shown that PJ/SAID consists several Strata (PJS) electron density and temperature. A new type phenomena has been discovered called Stratified Subauroral (SSAID), which a containing small‐scale PJS. Internal structure SSAIDs measured during various geomagnetic events using data from NorSat‐1, DMSP F‐17 F‐18 satellites. High resolution measurements on Norsat‐1 satellite make it...

During the 23 April 2023 geospace storm, we observed chorus wave-driven energetic particle precipitation on closed magnetic field lines in dayside magnetosphere. Simultaneously and ionosphere's bottom-side, signatures of impact ionization strong enhancements ionospheric electric strength, via radar-detection meter-scale turbulence with matching temporal characteristics. storms, then, turbulent structuring as well fast electrodynamics polar ionosphere can be driven by wave-particle interactions