Blar i Department of Physics and Technology på tidsskrift "Annales Geophysicae"
Viser treff 1-14 av 14
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The asymmetric geospace as displayed during the geomagnetic storm on 17 August 2001
(Peer reviewed; Journal article, 2018-11-29)Previous studies have shown that conjugate auroral features are displaced in the two hemispheres when the interplanetary magnetic field (IMF) has a transverse (Y) component. It has also been shown that a BY component is ... -
Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard
(Journal article; Peer reviewed, 2021)This study analyses the observations of a new type of small-scale aurora-like feature, which is further referred to as fragmented aurora-like emission(s) (FAEs). An all-sky camera captured these FAEs on three separate ... -
Cluster observations of a field aligned current at the dawn flank of a bursty bulk flow
(Peer reviewed; Journal article, 2007-06-29)This article describes observations of a bursty bulk flow (BBF) in the outer central plasma sheet. The observations are made with the Cluster satellites, located approximately 19RE downtail, close to the midnight sector ... -
Electron precipitation characteristics during isolated, compound, and multi-night substorm events
(Journal article; Peer reviewed, 2021)A set of 24 isolated, 46 compound, and 36 multi-night substorm events from the years 2008–2013 have been analysed in this study. Isolated substorm events are defined as single expansion–recovery phase pairs, compound ... -
Estimating the fate of oxygen ion outflow from the high-altitude cusp
(Journal article; Peer reviewed, 2020)We have investigated the oxygen escape-to-capture ratio from the high-altitude cusp regions for various geomagnetic activity levels by combining EDI and CODIF measurements from the Cluster spacecraft. Using a magnetic field ... -
The Hall current system revealed as a statistical significant pattern during fast flows
(Peer reviewed; Journal article, 2008-11-05)We have examined the dawn-dusk component of the magnetic field, BY , in the night side current sheet during fast flows in the neutral sheet. 237 h of Cluster data from the plasma sheet between 2 August 2002 and 2 October ... -
An investigation into the spectral parameters of ultra-low-frequency (ULF) waves in the polar caps and magnetotail
(Journal article; Peer reviewed, 2022)The present case study is focused on fluctuations at ∼ 1.5 mHz observed on open field lines in both of the polar caps in ground-based geomagnetic data and in the electron concentration in the Northern Hemisphere ionosphere. ... -
Lower-thermosphere–ionosphere (LTI) quantities: current status of measuring techniques and models
(Journal article; Peer reviewed, 2021)The lower-thermosphere–ionosphere (LTI) system consists of the upper atmosphere and the lower part of the ionosphere and as such comprises a complex system coupled to both the atmosphere below and space above. The atmospheric ... -
Observations of precipitation energies during different types of pulsating aurora
(Journal article; Peer reviewed, 2020)Pulsating aurora (PsA) is a diffuse type of aurora with different structures switching on and off with a period of a few seconds. It is often associated with energetic electron precipitation (>10 keV) resulting in the ... -
Observations of sunlit N2+ aurora at high altitudes during the RENU2 flight
(Journal article; Peer reviewed, 2021)We present measurements of sunlit aurora during the launch of the Rocket Experiment for Neutral Upwelling 2 (RENU2) on the 13 December 2015, 07:34 UTC. The in situ auroral conditions coincide with those of sunlit aurora ... -
Plasma density gradients at the edge of polar ionospheric holes: the absence of phase scintillation
(Journal article; Peer reviewed, 2020)Polar holes were observed in the high-latitude ionosphere during a series of multi-instrument case studies close to the Northern Hemisphere winter solstice in 2014 and 2015. These holes were observed during geomagnetically ... -
Simulated seasonal impact on middle atmospheric ozone from high-energy electron precipitation related to pulsating aurorae
(Journal article; Peer reviewed, 2021)Recent simulation studies have provided evidence that a pulsating aurora (PsA) associated with high-energy electron precipitation is having a clear local impact on ozone chemistry in the polar middle mesosphere. However, ... -
Three principal components describe the spatiotemporal development of mesoscale ionospheric equivalent currents around substorm onsets
(Journal article; Peer reviewed, 2023)Substorms are a commonly occurring but insufficiently understood form of dynamics in the coupled magnetosphere–ionosphere system, associated with space weather disturbances and auroras. We have used principal component ... -
Types of pulsating aurora: Comparison of model and EISCAT electron density observations
(Journal article; Peer reviewed, 2022)Energetic particle precipitation associated with pulsating aurora (PsA) can reach down to lower mesospheric altitudes and deplete ozone. It is well documented that pulsating aurora is a common phenomenon during substorm ...