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Spicher, Andres; Kvammen, Andreas; Zettergren, M.; Roglans, Roger; Bonnell, John W & LaBelle, James
[Vis alle 20 forfattere av denne artikkelen]
(2024).
Characterizing ionospheric turbulence on the poleward side of the cusp using sounding rocket observations and modelling work.
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Spicher, Andres; Rexer, Theresa; Kvammen, Andreas; Madhanakumar, Mahith; Zettergren, M. & Oksavik, Kjellmar
[Vis alle 11 forfattere av denne artikkelen]
(2024).
Characterization and Assessment of Structuring Connected to Auroral Dynamics using EISCAT_3D (CASCADE): A brief overview.
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Madhanakumar, Mahith; Spicher, Andres; Vierinen, Juha-Pekka & Oksavik, Kjellmar
(2024).
Source regions of irregularities causing GNSS radio scintillation: An investigation using EISCAT.
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Huyghebaert, Devin Ray; Gustavsson, Björn Johan; Vierinen, Juha-Pekka; Spicher, Andres; Kvammen, Andreas & Zettergren, Matthew D.
(2023).
EISCAT_3D Imaging Techniques for Ionospheric Incoherent Scatter Spectra Reconstruction.
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Huyghebaert, Devin Ray; Chau, Jorge L.; Spicher, Andres; Ivarsen, Magnus Fagernes; Clausen, Matthias & Latteck, Ralph
[Vis alle 7 forfattere av denne artikkelen]
(2023).
Large Scale Temporal and Spatial Characteristics of E-region Plasma Irregularities Measured by SIMONe Norway.
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Gavazzi, Etienne Robin Victor; Spicher, Andres; Gustavsson, Björn Johan; Clemmons, James H.; Pfaff, Robert F. & Rowland, Douglas E.
(2023).
Time dependent electron transport calculations of the ionospheric response to Alfvénic precipitations.
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Spicher, Andres
(2023).
Space physics at UiT The Arctic University of Norway, Tromsø.
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Rexer, Theresa; Spicher, Andres; Kvammen, Andreas & Vierinen, Juha
(2023).
Characteristics of polar ionospheric plasma density irregularities with multi-point measurements.
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Rexer, Theresa; Spicher, Andres; Vierinen, Juha & Kvammen, Andreas
(2023).
Exploring Characteristics of Turbulent Density Fluctuations in the Arctic Ionosphere with Multi-Point Measurements.
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Spicher, Andres; Kvammen, Andreas; LaBelle, James; Zettergren, Matthew D.; Bonnell, John W. & Roglans, Roger
[Vis alle 20 forfattere av denne artikkelen]
(2023).
Examining the relevance of different instability mechanisms in causing ionospheric cusp irregularities based on sounding rocket data and numerical simulations.
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Kvammen, Andreas; Spicher, Andres; Zettergren, Matthew D.; Huyghebaert, Devin Ray; Rexer, Theresa & Gustavsson, Björn Johan
[Vis alle 7 forfattere av denne artikkelen]
(2023).
Conditions for the Kelvin-Helmholtz Instability in the Polar Ionosphere.
Vis sammendrag
The polar ionosphere is highly structured with density irregularities observed at a wide range of scale sizes: small scale (< 1 km), meso-scale (1–100 km) and large scale (> 100 km). Plasma irregularities are of interest since they may disturb Global Navigation Satellite Systems (GNSS) signals and disrupt High Frequency (HF) communication. Still, the conditions for the formation, the energy cascading from large to small scales and the non-linear evolution of plasma instabilities that cause irregularities in the polar ionosphere are largely unknown. This poster focuses on examining one of the most commonly invoked instabilities at high latitudes: the Kelvin-Helmholtz instability. The Kelvin-Helmholtz instability can be excited when there exists a shear in the flow velocity. At polar latitudes, flow shears are often observed in relation to auroral arcs, flow channels and reverse flow events. In this work, we use the 3D Geospace Environment Model of Ion-Neutral Interactions (GEMINI) to simulate the Kelvin-Helmholtz instability under various ionospheric conditions. This allows us to characterize the conditions favorable for Kelvin-Helmholtz instability growth. The presented results can be used as a reference to better understand observations of density irregularities under turbulent conditions at high latitudes.
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Spicher, Andres
(2023).
Characterizing high-latitude ionospheric turbulence.
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Buschmann, Lisa Marie; Spicher, Andres; Clausen, Lasse; Marholm, Sigvald & Miloch, Wojciech Jacek
(2022).
Role of particle precipitation on plasma structuring at different altitudes by in-situ measurements.
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Spicher, Andres
(2022).
High-latitude ionospheric density turbulence.
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Spicher, Andres; Vierinen, Juha; Oksavik, Kjellmar; Jin, Yaqi; Huyghebaert, Devin Ray & Madhanakumar, Mahith
(2022).
Multi-instrument multi-scale characterization of ionospheric irregularities in the cusp region.
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Spicher, Andres; LaBelle, James William; Bonnell, John W.; Roglans, Roger; Moser, Chrystal & Fuselier, Stephen A.
[Vis alle 18 forfattere av denne artikkelen]
(2022).
Sounding rocket investigation of multi-scale (density) irregularities in the cusp region.
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Spicher, Andres; Vierinen, Juha; Oksavik, Kjellmar & Jin, Yaqi
(2022).
Statistical characteristics of ionospheric irregularities in the cusp ionosphere based on multi-instrument techniques.
Vis sammendrag
Plasma density irregularities disturbing signals from Global Navigation Satellite Systems (GNSS) are known to be regular features of the high-latitude ionosphere, especially around the cusp and auroral regions. Despite their relevance for society, irregularity formation and evolution are still relatively poorly understood, and observations revealing the spatio-temporal characteristics of ionospheric structuring at different scales are needed to assess the exact mechanism(s) responsible for them.
In this study, we focus on data from the European Incoherent Scatter Scientific Association (EISCAT) Svalbard Radars (ESR) operating in fast scanning mode. We use ESR experiments in which the antenna was swept in elevation, and create consecutive two-dimensional images showing how electron density, ion velocity, electron temperature, and ion temperatures change with latitude and time at different altitudes.
We present selected events in which the ESR scans are combined with all-sky images and in-situ data from the Swarm satellites to provide multi-scale observations of cusp phenomena comprising polar cap patches, flow channels, particle precipitation, and ion heating. We compare the observations with the presence of GNSS scintillations, allowing to monitor the onset and development of irregularities causing scintillations, and to inspect their connection with the phenomena above-mentioned. We then extend the analysis by performing a statistical study using all ESR fast scans identified between January 2001 and December 2015. We investigate the statistical characteristics of the measured parameters at different altitudes and under different geomagnetic conditions. Overall, this study will provide further insights onto the spatio-temporal evolution of ionospheric cusp dynamics, and on the possible physical sources causing ionospheric irregularities with Space weather impacts.
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Di Mare, Francesca; Spicher, Andres; Clausen, Lasse; Miloch, Wojciech Jacek; Takahashi, Toru & Moen, Jøran Idar
(2021).
Turbulence and Intermittency in the Winter Cusp Ionosphere studied with the ICI Sounding Rockets .
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Spicher, Andres & Vierinen, Juha
(2021).
On the spatio-temporal characteristics of cusp structuring using the EISCAT Svalbard radars in scanning mode.
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Spicher, Andres; Moen, Jøran Idar; LaBelle, James William; Bonnell, John W; Roglans, Roger & Moser, Chrystal
[Vis alle 18 forfattere av denne artikkelen]
(2021).
Sounding rocket studies of ionospheric turbulence above Svalbard.
Vis sammendrag
Every morning between about 06 UT and 11 UT, Svalbard rotates just below the cusps (dayside aurora), where direct coupling between the solar wind, magnetosphere and ionosphere occurs. This provides a unique window to study the dayside aurora and the highly dynamic processes associated with it, examples of which include electron and ion precipitation and heating, electrostatic and electromagnetic waves, as well as turbulence.
In this work, we focus on the turbulence which, alongside with being of pure scientific interest, can also have societal impacts. Indeed, the “irregular” electron density structures associated with it can affect our technology infrastructures by for instance degrading High Frequency (HF) communication and Global Navigation Satellite Systems (GNSS) signals.
After briefly reviewing some of the mechanisms believed to be important in the development of turbulence in the high-latitude ionosphere, we present recent observations of density irregularities obtained by sounding rockets above Svalbard. We focus on measurements made as a part of the
Grand Challenge Initiative (GCI) Cusp, an international project combining sounding rockets missions and ground-based instruments to study the cusps. We show detailed characterization of the nature of the irregularities including their phase velocity and wavelengths, helping shedding light onto the process(es) involved in their formation, especially at the scales important for Space weather applications.
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Miloch, Wojciech Jacek; Jin, Yaqi; Xiong, Chao; Brask, Steffen Mattias; Kotova, Daria & Kervalishvili, Guram
[Vis alle 9 forfattere av denne artikkelen]
(2020).
Ionospheric Plasma IRregularities (IPIR data products).
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Spicher, Andres; LaBelle, James William; Bonnell, John W; Bounds, Scott; Clausen, Lasse Boy Novock & Di Mare, Francesca
[Vis alle 16 forfattere av denne artikkelen]
(2020).
On multi-scale density irregularities observed by sounding rockets within regions of enhanced scintillations in the cusp ionosphere.
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Di Mare, Francesca; Spicher, Andres; Clausen, Lasse Boy Novock; Miloch, Wojciech Jacek & Moen, Jøran Idar
(2020).
Turbulent Signatures in the Polar Cusp Ionosphere
using sounding rocket mission observations
.
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Di Mare, Francesca; Spicher, Andres; Clausen, Lasse Boy Novock; Miloch, Wojciech Jacek & Moen, Jøran Idar
(2020).
Turbulence Signatures in the Polar/Cusp Ionosphere based on ICI sounding rocket missions
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Miloch, Wojciech Jacek; Kotova, Daria; Jin, Yaqi; Xiong, Chao; Brask, Steffen & Kervalishvili, Guram
[Vis alle 9 forfattere av denne artikkelen]
(2019).
Ionospheric plasma irregularities studied globally with the Swarm satellites
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Di Mare, Francesca; Spicher, Andres; Clausen, Lasse Boy Novock & Moen, Jøran Idar
(2019).
Turbulence observations in the Polar/Cusp Ionosphere using ICI sounding rocket data.
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Di Mare, Francesca; Spicher, Andres; Clausen, Lasse Boy Novock & Moen, Jøran Idar
(2019).
Mapping of turbulence at the high-latitude Ionosphere using ICI-2 and ICI-3 sounding rocket data.
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Di Mare, Francesca; Spicher, Andres; Clausen, Lasse Boy Novock & Moen, Jøran Idar
(2019).
Turbulence observations in the Polar/Cusp Ionosphere using ICI data missions.
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Spicher, Andres; Moen, Jøran Idar; Clausen, Lasse Boy Novock & Miloch, Wojciech Jacek
(2019).
On the source and nature of ionospheric plasma irregularities: advances made through the Investigation of Cusp irregularities sounding rocket program .
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Spicher, Andres & Røed, Ketil
(2019).
Verdensrommet av muligheter Studenter i spennende romforskningsprosjekter
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Clemmons, J.H.; Rowland, Douglas E.; Hecht, J. H.; Pfaff, Robert F.; Michell, Robert & Moen, Jøran Idar
[Vis alle 10 forfattere av denne artikkelen]
(2019).
VISIONS-2 Observations of Electron Dynamics and Alfvén Waves.
Vis sammendrag
Results from last year’s VISIONS-2 sounding rocket mission to investigate the physics of the cusp are presented and discussed. The focus is on the relationship of the highly-structured, field-aligned, dispersed electron fluxes and the concurrently-measured low frequency electric and magnetic fields, which are taken to be Alfvén waves. The discussion centers on the copious appearance of these phenomena within the VISIONS-2 measurements, and discusses the distinct characteristics of the electron bursts in the context of the waves. Featured are Poynting flux calculations (magnitude and direction) of the waves and a characterization of the wave polarization relative to the direction of the mean plasma flow. Energy analyses of the electrons and waves are used to elucidate their interrelationship, and time-of-flight analyses are used to constrain the interaction domain in the vertical direction.
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Pfaff, Robert F.; Rowland, Douglas E.; Freudenreich, H.; Clemmons, J.H.; Moen, Jøran Idar & Oksavik, Kjellmar
[Vis alle 8 forfattere av denne artikkelen]
(2019).
Dual Sounding Rocket Observations of Plasma Convection and Shear, Field-aligned Currents, and Alfven waves and Irregularities in the Cusp during IMF Bz Negative Conditions.
Vis sammendrag
On December 7, 2018, two NASA Black Brant X sounding rockets were launched simultaneously from Ny Ålesund, Spitzbergen (79˚ N) into the dayside cusp and subsequently cut across the open/closed field line boundary, reaching apogees of 601 km and 807 km. The launches occurred during Bz negative conditions. We provide an overview of the electrodynamic observations and focus on the DC electric field results, available from the lower altitude rocket, and field-aligned currents, observed on both rockets. The in situ DC electric fields reveal highly dynamic, structured flows within the cusp with steady flow towards the north and afternoon sector poleward of the cusp. Just equatorward of the cusp, strong meridional electric fields associated with westward plasma flow is observed in conjunction with zonal magnetic field perturbations, indicative of strong field-aligned currents. We discuss the large scale electrodynamics, including plasma shears and currents, as signatures of the open/closed character of the cusp/low latitude boundary layer as a function of the IMF. The electric field, magnetic field, and plasma density data also reveal strong ULF/ELF plasma waves and irregularities that exist within the open magnetic field line cusp region yet disappear when the payload was equatorward of the cusp on closed magnetic field lines. We present detailed wave characteristics and discuss them in terms of Alfvén waves and static irregularities that pervade the cusp region yet change character as a function of altitude.
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Spicher, Andres; Deshpande, Kshitija; Zettergren, Matthew D.; Oksavik, Kjellmar; Jin, Yaqi & Clausen, Lasse Boy Novock
[Vis alle 7 forfattere av denne artikkelen]
(2019).
Modeling scintillation produced by ionospheric Kelvin Helmholtz in the cusp ionosphere using GEMINI-SIGMA.
Vis sammendrag
Ionospheric irregularities are known to cause fluctuations in radio signals called scintillation in the phase and amplitude of the complex signal. The turbulent structures responsible for the scintillation are a few hundreds of meters to few tens of kilometers scale sizes (intermediate scale sizes). With the growing interest in high latitude scintillation, we would like to investigate the effect of typical physical mechanisms on the radio scintillation.
Here we present our modeling studies of Global Positioning System (GPS) scintillation through Kelvin Helmholtz instability (KHI) in the cusp region. For modeling we use the first principles based Geospace Environment Model of Ion-Neutral Interactions (GEMINI) and Satellite-beacon Ionospheric-scintillation Global Model of the upper Atmosphere (SIGMA). We utilize a cusp event study with detailed observations from the EISCAT Svalbard Radar (ESR) and scintillations detected from a network of four Global Navigation Satellite Systems (GNSS) receivers in Svalbard. The event presents evidences of the role of magnetosphere-ionosphere coupling in the generation of plasma irregularities and scintillations in the cusp. Using numerical simulations, we investigate the potential role of the Kelvin-Helmholtz instability in producing such scintillation. Furthermore, we compare the results with characteristics of GPS scintillations associated with a polar cap patch and the gradient drift instability to deduce distinctive characteristics of the respective plasma irregularities.
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Moser, Chrystal; LaBelle, James William; Kletzing, Craig A.; Bounds, Scott; Hatch, Spencer Mark & Oksavik, Kjellmar
[Vis alle 12 forfattere av denne artikkelen]
(2019).
CAPER-2 and TRICE-2 Sounding Rocket Investigations: Whistler and Upper-Hybrid Waves in the Polar Cusp.
Vis sammendrag
The CAPER-2 and TRICE-2 sounding rockets launched 4 January 2019 and 8 December 2018, respectively, into the cusp of earth’s magnetic field as part of the Grand Challenge Initiative to study cusp dynamics. Both of these missions carried receivers to examine auroral radio emissions ranging from a few hertz to several megahertz allowing for fine structures within the spectra to be observed. For instance, on field lines from 300-1300 km equator-ward of the estimated cusp boundary, CAPER-2 VLF receivers observed saucer-like features in its time-frequency spectra. Although superficially similar to those seen by James [1976], these features extend over a far greater spatial extent implying a much more distant source, perhaps > 10,000 km above the space- craft. Because the plasma and the magnetic field are not uniform over such a large altitude range, ray tracing will be required to interpret these features, and determine whether or not they originate in the cusp. HF receivers aboard TRICE-2 observed several intervals of intense non-thermal upper-hybrid waves with banded-structures, having 4-12 bands with spacings and bandwidths of about 5 kHz. Two possible explanations for these features are: 1) modulation from wave-wave interactions of upper-hybrid waves with lower-hybrid/whistler waves, or 2) the HF antennas have a separation equal to an integral number of the observed wavelength resulting in nulls within the spectra. Data from the UCB VLF receivers shows lower-hybrid cutoff near 5 kHz, suggesting the presence of a wave-wave interaction. Consideration of rocket probe attitude is required to test these and other mechanisms. Both CAPER-2 and TRICE-2 observed a host of other wave and particle phenomena in the cusp that need to be investigated further to enhance our understanding of the auroral ionosphere and magnetospheric-ionospheric interactions.
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Follestad, Anna Kristine Fæhn; Herlingshaw, Katie; Ghadjari, Hossein; Knudsen, David J.; McWilliams, Kathryn A. & Moen, Jøran Idar
[Vis alle 9 forfattere av denne artikkelen]
(2019).
Birkeland Current Impacts on Cusp Ionospheric Irregularities.
Vis sammendrag
Global Navigation Satellite System (GNSS) scintillations at high latitudes have traditionally been attributed to the Gradient Drift Instability (GDI) associated with polar cap patches and flow shear instabilities such as the Kelvin-Helmholtz Instability (KHI). Previous studies have also shown that electron precipitation may play an important role for scintillations in the cusp. In this study, we combine in situ Swarm data with GNSS observations from a network of three ground based receivers around Svalbard, Norway, to further investigate the role of particle precipitation on phase scintillations in the cusp region. In particular, we examine the relation between strong scintillations and finely structured Birkeland currents. For this purpose, we identified 23 events in the winter time cusp with phase scintillations >0.45 radians. We show consistent colocation between enhanced cusp scintillations and regions of filamented Birkeland currents. In addition, we relate the observations to the presence of turbulence and dispersive Alfvén waves. The observations suggest that the filamentary field aligned currents and related particle precipitations in themselves together may act as the primary driver for the creation of irregularities responsible for ground based phase scintillations measured underneath the cusp.
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Rowland, Douglas E.; Moen, Jøran Idar; Pfaff, Robert F.; Clemmons, J.H.; Spicher, Andres & Freudenreich, H.
[Vis alle 16 forfattere av denne artikkelen]
(2019).
VISIONS-2 observations of ion heating and energization near the exobase, and the role of wave-particle interactions.
Vis sammendrag
The VISIONS-2 sounding rocket mission, launched Dec 7, 2019 into the cusp, was predominantly designed to study ion outflow acceleration mechanisms. It carried a variety of in situ particles and fields sensors to diagnose ion energization and heating mechanisms, as well as remote sensing instrumentation to image the energy inputs (rocket-borne visible wavelength multispectral auroral imager) and ion outflow (energetic neutral atom imager). The Kjell Henriksen Observatory (KHO) optical instruments and the EISCAT radar were used to measure the conditions before, during, and after the VISIONS-2 launch. VISIONS-2 observed strong cusp outflow of <20 eV ions at altitudes at and below 600 km. Uniquely, VISIONS-2 flew two payloads on nearly the same set of field lines, but separated by 200 km. They both observed intense VLF wave activity, but only the higher one (~800 km apogee) observed significant ELF wave activity. We will describe the VISIONS-2 observations of the ion acceleration and compare to simple models of wave-particle heating by VLF and ELF waves, and discuss the overall mechanism (potentially Alfven waves coupling to LH which then directly heat the ions).
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Rowland, Douglas E.; Moen, Jøran Idar; Pfaff, Robert F.; Clemmons, J.H.; Spicher, Andres & Freudenreich, H.
[Vis alle 16 forfattere av denne artikkelen]
(2019).
VISIONS-2 observations of the electrodynamics of magnetosphere-ionosphere coupling.
Vis sammendrag
The VISIONS-2 sounding rocket mission, launched Dec 7, 2019 into the cusp, was predominantly designed to study ion outflow acceleration mechanisms. However, its rocket-borne and ground-based instrument complement was well suited to study the electrodynamics of the cusp, including the pathways of magnetosphere-ionosphere coupling. VISIONS-2 launched southward from Ny Alesund, Svalbard, under active cusp conditions, with southward Bz and positive Bx and negative By. The Kjell Henriksen Observatory (KHO) optical instruments and the EISCAT radar were used to measure the conditions before, during, and after the VISIONS-2 launch. VISIONS-2 observed strong convection indicative of a potential penetration into the afternoon convection cell, strong Alfvénic activity, and intense filamentary soft precipitation. VISIONS-2's unique combination of rocket borne multispectral imagery along with in situ instrumentation of particles and fields as well as the ground-based measurements provide a unique view of the M-I coupling processes taking place at this time. We will describe the VISIONS-2 observations of the large-scale electrodynamics and discuss how the observations fit into our understanding of cusp processes.
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Spicher, Andres; Oksavik, Kjellmar; Jin, Yaqi; Clausen, Lasse Boy Novock; Zettergren, Matthew D. & Deshpande, K. B.
[Vis alle 8 forfattere av denne artikkelen]
(2019).
A reverse flow event as the onset of ionospheric scintillation irregularities in the cusp.
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Spicher, Andres; Oksavik, Kjellmar; Jin, Yaqi; Moen, Jøran Idar; Baddeley, Lisa & Clausen, Lasse Boy Novock
(2019).
On the sources of Cusp Ionospheric Scintillation Irregularities.
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Spicher, Andres; Moen, Jøran Idar; Clausen, Lasse Boy Novock; Miloch, Wojciech Jacek & Blix, Kolbjørn
(2018).
4DSpace long term plans towards a multi-satellite M-Class mission.
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Spicher, Andres; Clausen, Lasse Boy Novock; Miloch, Wojciech Jacek; Jin, Yaqi; Lofstad, Victoria Emilie & Moen, Jøran Idar
(2018).
Polar cap patch climatology based on Swarm density data.
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Spicher, Andres & Røed, Ketil
(2018).
Verdensrommet av muligheter Studenter i spennende romforskningsprosjekter.
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Spicher, Andres
(2018).
In situ studies of irregularities in the cusp ionosphere.
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Spicher, Andres; Moen, Jøran Idar; Hoang, Huy Minh; Røed, Ketil; Trondsen, Espen & Miloch, Wojciech Jacek
[Vis alle 7 forfattere av denne artikkelen]
(2018).
The Investigation of Cusp irregularities 5 sounding rocket: multi-point measurement of turbulence.
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Spicher, Andres & Moen, Jøran Idar
(2018).
How to successfully launch a sounding rocket from Norway.
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Moen, Jøran Idar; Oksavik, Kjellmar; Carlson, Herbert C; Spicher, Andres; Bekkeng, Tore Andre & Clausen, Lasse Boy Novock
[Vis alle 11 forfattere av denne artikkelen]
(2018).
The Investigation of Cusp Irregularities Rocket Program.
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Jin, Yaqi; Miloch, Wojciech Jacek; Clausen, Lasse Boy Novock; Spicher, Andres; Stolle, Claudia & Kervalishvili, G.
[Vis alle 7 forfattere av denne artikkelen]
(2018).
Ionospheric Plasma Irregularities Characterized by the Swarm satellites.
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Jin, Yaqi; Spicher, Andres; Xiong, Chao; Clausen, Lasse Boy Novock; Stolle, Claudia & Kervalishvili, G.
[Vis alle 7 forfattere av denne artikkelen]
(2018).
Detecting high-latitude ionospheric plasma irregularities by Swarm satellites.
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Moen, Jøran Idar; Oksavik, Kjellmar; Carlson, Herbert C; Stausland, Christoffer T; Clausen, Lasse Boy Novock & Daabakk, Yvonne
[Vis alle 12 forfattere av denne artikkelen]
(2017).
Kelvin Helmholtz and Gradient Drift instabilities in ionosphere cusp flow channels.
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Spicher, Andres
(2017).
Multiscale characterization of plasma irregularities in the polar ionosphere using in situ measurements.
7Letras.
