Blar i Bergen Open Research Archive på forfatter "Kwagala, Norah Kaggwa"
-
Asymmetrically Varying Guide Field During Magnetic Reconnection: Particle-In-Cell Simulations
Spinnangr, Susanne Flø; Tenfjord, Paul Arne Riksheim; Hesse, Michael; Norgren, Astrid Elisabet Cecilia; Kolstø, Håkon Midthun; Kwagala, Norah Kaggwa; Jørgensen, Therese; Jimenez, Judit Perez-Coll (Journal article; Peer reviewed, 2022)Using fully kinetic particle-in-cell modeling, we investigate how magnetic reconnection responds to a varying guide field in one of the inflow regions. We find that the reconnection rate varies significantly when the ... -
Collisionless Magnetic Reconnection in an Asymmetric Oxygen Density Configuration
Kolstø, Håkon Midthun; Hesse, Michael; Norgren, Astrid Elisabet Cecilia; Tenfjord, Paul; Spinnangr, Susanne Flø; Kwagala, Norah Kaggwa (Journal article; Peer reviewed, 2020)Combined with the magnetic field, the distribution of charged particles in the inflow region is expected to control the rate of magnetic reconnection. This paper investigates how the reconnection process is altered by a ... -
Comparing Three Approaches to the Inducing Source Setting for the Ground Electromagnetic Field Modeling due to Space Weather Events
Marshalko, Elena; Kruglyakov, Mikhail; Kuvshinov, Alexey; Juusola, Liisa; Kwagala, Norah Kaggwa; Sokolova, Elena; Pilipenko, Vyacheslav (Journal article; Peer reviewed, 2020)Ground-based technological systems, such as power grids, can be affected by geomagnetically induced currents (GIC) during geomagnetic storms and magnetospheric substorms. This motivates the necessity to numerically simulate ... -
Electron Behavior Around the Onset of Magnetic Reconnection
Spinnangr, Susanne Flø; Hesse, Michael; Tenfjord, Paul Arne Riksheim; Norgren, Cecilia; Kolstø, Håkon Midthun; Kwagala, Norah Kaggwa; Jørgensen, Therese; Phan, Tai D. (Journal article; Peer reviewed, 2022)We investigate the onset of magnetic reconnection, utilizing a fully kinetic Particle-In-Cell (PIC) simulation. Characteristic features of the electron phase-space distributions immediately before reconnection onset are ... -
How Often Do Thermally Excited 630.0 nm Emissions Occur in the Polar Ionosphere?
Kwagala, Norah Kaggwa; Oksavik, Kjellmar; Lorentzen, Dag Arne; Johnsen, Magnar Gullikstad (Peer reviewed; Journal article, 2018-01)This paper studies thermally excited emissions in the polar ionosphere derived from European Incoherent Scatter Svalbard radar measurements from the years 2000–2015. The peak occurrence is found around magnetic noon, where ... -
Interaction of Cold Streaming Protons with the Reconnection Process
Tenfjord, Paul; Hesse, Michael; Norgren, Astrid Elisabet Cecilia; Spinnangr, Susanne Flø; Kolstø, Håkon Midthun; Kwagala, Norah Kaggwa (Journal article; Peer reviewed, 2020)We employ a 2.5D particle-in-cell simulation to study a scenario where the reconnection process captures cold streaming protons. As soon as the tailward streaming protons become involved, they contribute to the overall ... -
Magnetospheric Multiscale Observations of an Expanding Oxygen Wave in Magnetic Reconnection
Kolstø, Håkon Midthun; Norgren, Astrid Elisabet Cecilia; Hesse, Michael; Chen, Li-Jen; Tenfjord, Paul; Spinnangr, Susanne Flø; Kwagala, Norah Kaggwa (Journal article; Peer reviewed, 2021)Heavier plasma species such as oxygen ions can have a large impact on the magnetic reconnection process. It has been hypothesized that the acceleration of demagnetized oxygen ions by the Hall electric field will lead to ... -
The Micro-Macro Coupling of Mass-Loading in Symmetric Magnetic Reconnection With Cold Ions
Spinnangr, Susanne Flø; Hesse, Michael; Tenfjord, Paul Arne Riksheim; Norgren, Astrid Elisabet Cecilia; Kolstø, Håkon Midthun; Kwagala, Norah Kaggwa; Jørgensen, Therese Moretto (Journal article; Peer reviewed, 2021)We investigate how magnetic reconnection is influenced by an inflow of a dense cold ion population. We compare two 2.5D Particle-In-Cell simulations, one containing the cold population and one without. We find that the ... -
A new Look at the Electron Diffusion Region in Asymmetric Magnetic Reconnection
Hesse, Michael; Norgren, Astrid Elisabet Cecilia; Tenfjord, Paul; James L., Burch; Liu, Yi‐Hsin; Bessho, Naoki; Wang, Shan; Kolstø, Håkon Midthun; Spinnangr, Susanne Flø; Ergun, Robert E; Moretto, Therese; Kwagala, Norah Kaggwa (Journal article; Peer reviewed, 2021)A new look at the structure of the electron diffusion region in collision less magnetic reconnection is presented. The research is based on a particle-in-cell simulation of asymmetric magnetic reconnection, which includes ... -
On the contribution of thermal excitation to the total 630.0 nm emissions in the northern cusp ionosphere
Kwagala, Norah Kaggwa; Oksavik, Kjellmar; Lorentzen, Dag Arne; Johnsen, Magnar Gullikstad (Peer reviewed; Journal article, 2017-01)Direct impact excitation by precipitating electrons is believed to be the main source of 630.0 nm emissions in the cusp ionosphere. However, this paper investigates a different source, 630.0 emissions caused by thermally ... -
On the Impact of a Streaming Oxygen Population on Collisionless Magnetic Reconnection
Kolstø, Håkon Midthun; Hesse, Michael; Norgren, Astrid Elisabet Cecilia; Tenfjord, Paul; Spinnangr, Susanne Flø; Kwagala, Norah Kaggwa (Journal article; Peer reviewed, 2020)Using 2.5-D Particle-In-Cell (PIC) simulations, we investigate how magnetotail reconnection is affected by a cold, streaming, oxygen plasma population, attributed to an ionospheric source, in the inflow region. As the ... -
On the Presence and Thermalization of Cold Ions in the Exhaust of Antiparallel Symmetric Reconnection
Norgren, Astrid Elisabet Cecilia; Tenfjord, Paul Arne Riksheim; Hesse, Michael; Toledo-Redondo, Sergio; Li, Wenya; Xu, Yin; Kwagala, Norah Kaggwa; Spinnangr, Susanne Flø; Kolstø, Håkon Midthun; Moretto, Therese (Journal article; Peer reviewed, 2021)Using fully kinetic 2.5 dimensional particle-in-cell simulations of anti-parallel symmetric magnetic reconnection, we investigate how initially cold ions are captured by the reconnection process, and how they evolve and ... -
The Role of Resistivity on the Efficiency of Magnetic Reconnection in MHD
Jimenez, Judit Perez-Coll; Tenfjord, Paul Arne Riksheim; Hesse, Michael; Norgren, Astrid Elisabet Cecilia; Kwagala, Norah Kaggwa; Kolstø, Håkon Midthun; Spinnangr, Susanne Flø (Journal article; Peer reviewed, 2022)Using a resistive MagnetoHydroDynamic (MHD) simulation, we study how the magnitude and shape of diffusion influence magnetic reconnection. Specifically, we investigate how and why the reconnection rate is influenced by ... -
Seasonal and Solar Cycle Variations of Thermally Excited 630.0 nm Emissions in the Polar Ionosphere
Kwagala, Norah Kaggwa; Oksavik, Kjellmar; Lorentzen, Dag Arne; Johnsen, Magnar Gullikstad; Laundal, Karl Magnus (Peer reviewed; Journal article, 2018-08)Solar cycle and seasonal variations have been found in the occurrence of strong thermally excited 630.0 nm emissions in the polar ionosphere. Measurements from the European Incoherent Scatter Svalbard Radar have been used ... -
Thermally excited 630.0 nm emissions in the polar ionosphere
Kwagala, Norah Kaggwa (Doctoral thesis, 2018-08-24)This thesis investigates the importance and significance of thermally excited 630.0 nm emissions in the cusp and polar ionosphere. Thermal excitation by heated ambient electrons in the cusp and polar ionosphere is a rarely ... -
Validating the Space Weather Modeling Framework (SWMF) for applications in northern Europe: Ground magnetic perturbation validation
Kwagala, Norah Kaggwa; Hesse, Michael; Moretto, Therese; Tenfjord, Paul; Norgren, Astrid Elisabet Cecilia; Tóth, Gábor; Gombosi, Tamás I.; Kolstø, Håkon Midthun; Spinnangr, Susanne Flø (Journal article; Peer reviewed, 2020)In this study we investigate the performance of the University of Michigan’s Space Weather Modeling Framework (SWMF) in prediction of ground magnetic perturbations (ΔB) and their rate of change with time (dB/dt), which is ...