A5002754818- Electromagnetic Scattering and Analysis
- Electromagnetic Simulation and Numerical Methods
- Atmospheric Ozone and Climate
- Ionosphere and magnetosphere dynamics
- Atmospheric chemistry and aerosols
- Matrix Theory and Algorithms
- Solar and Space Plasma Dynamics
- Photonic Crystals and Applications
- Geophysics and Gravity Measurements
- Earthquake Detection and Analysis
- Numerical methods in inverse problems
- Geomagnetism and Paleomagnetism Studies
- Cryospheric studies and observations
- Atmospheric and Environmental Gas Dynamics
- Microwave and Dielectric Measurement Techniques
- Optical Coatings and Gratings
- Vibration and Dynamic Analysis
- GNSS positioning and interference
- Advanced Numerical Methods in Computational Mathematics
- Astro and Planetary Science
- Microwave Engineering and Waveguides
- Climate variability and models
- Ocean Acidification Effects and Responses
- Numerical methods in engineering
- Photonic and Optical Devices
Umeå University
2016-2025
Swedish Institute of Space Physics
2025
Statistics Sweden
2016-2017
Argentine Antarctic Institute
2005-2011
Solar activity significantly influences the Earth's magnetosphere and ionosphere, causing current systems space weather effects. The interaction between rapidly changing magnetic field Earth’s conductivity induces an electric at surface producing Geomagnetically Induced Currents (GICs) within critical human infrastructure, posing a risk of damage to power lines.GICs strongly depend on ground conductivity. Sweden has large spatial variations complexity in underlying structure across...
Variations in the ionospheric currents can cause rapid disturbances magnetic field at ground level, so called dB/dt spikes, and Geomagnetically Induced Currents (GICs) that harm human infrastructure. When investigating spike occurrence GIC risks, focus has typically been on geomagnetic storms. However, recently it argued is substorm phenomena which contains crucial physics for spikes GICs, instead should be focus. Here we present results from a statistical investigation of substorms...
We present an efficient and interactive framework for the enhanced exploration, interpretation scientific analysis of spatio-temporal volumetric ionospheric data. The strategy is targeted at monitoring process adaptive experiments, offering a fast decision-making through real-time data processing, employing wide range tools in order to interpret In our computational module, high-resolution smooth volume images are generated from Incoherent Scatter Radar (ISR) data, which implements flexible...
Abstract The record of O3 total column and NO2 obtained by visible spectroscopy at Ushuaia (55° S), Marambio (64° S) Belgrano (78° vertical ozone profiles from the latter station provide insight into unprecedented major warming observed above Antarctica in last week September 2002. From 18 to 25 temperature increased 54°C isentropic level 700 K. anomaly was down 300 K which a well‐defined tropopause established. comparison before during event, it can be seen that fast increase took place...
This paper presents a preliminary analysis of the variations critical frequency F2 region (foF2) and total electron content (TEC) derived from Global Positioning System (GPS) data. Hourly foF2 values were scaled ionograms recorded at San Martin (68.1°S, 293.0°E) TEC GPS observations O’Higgins (63.3°S, 302.5°E). The database includes measurements obtained under different seasonal solar activity conditions. study shows that daily peak occurs around local noon in winter fall, spring secondary...
Abstract Spatio‐temporal variations of ionospheric currents cause rapid magnetic field at ground level and Geomagnetically Induced Currents (GICs) that can be harmful for human infrastructure. The risk large excursions in the time derivative, “ dB / dt spikes”, is known to high during geomagnetic storms substorms. However, less about occurrence spikes non‐stormy times. We use data from ground‐based globally covering magnetometers (SuperMAG database) years 1985–2021. investigate spike (| |...
In this paper, we consider a sorting scheme for potentially spurious scattering resonant pairs in one- and two-dimensional electromagnetic problems three-dimensional acoustic problems. The novel is based on Lippmann-Schwinger type of volume integral equation can, therefore, be applied to structures with graded materials as well configurations including piece-wise constant material properties. For TM/TE polarized waves waves, compute first approximations resonances finite elements. Then,...
Incoherent scatter radar (ISR) techniques provide reliable measurements for the analysis of ionospheric plasma. Measurements electron and ion densities, temperatures, line-of-sight velocities are derived by employing antennas that transmit receive radio waves. Recent developments in ISR technologies capable generating high-resolution volumetric data from multiple beam measurements. Examples such employ so-called phased array like AMISR North America or upcoming EISCAT_3D northern...
Abstract In this project, we consider the shape optimization of a dielectric scatterer aiming at efficient directional routing light. studied setting, light interacts with penetrable dimension comparable to wavelength an incoming planar wave. The design objective is maximize scattering efficiency inside target angle window. For this, Helmholtz problem piecewise constant refractive index medium models wave propagation, and accurate Dirichlet‐to‐Neumann map exterior domain. strategy consists...
In the quest for development of faster and more reliable technologies, ability to control propagation, confinement, emission light has become crucial. The design guide mode resonators perfect absorbers proven be fundamental importance. this project, we consider shape optimization a periodic dielectric slab aiming at efficient directional routing reproduce similar features resonator. For this, objective is maximize efficiency an incoming wave. That is, goal promote wave propagation along...
In this paper, we discuss problems arising when computing resonances with a finite element method. the pre-asymptotic regime, detect for one dimensional case, spurious solutions in computations of computational domain is truncated perfectly matched layer (PML) as well Dirichlet-to-Neumann map (DtN). The new test based on Lippmann-Schwinger equation and use pseudospectrum to show that suitable choice. Numerical simulations indicate presented can distinguish between eigenvalues true also...
We present an efficient procedure for computing resonances and resonant modes of Helmholtz problems posed in exterior domains. The problem is formulated as a nonlinear eigenvalue (NEP), where the nonlinearity arises from use Dirichlet-to-Neumann map, which accounts modeling unbounded consider variational formulation show that spectrum consists isolated eigenvalues finite multiplicity only can accumulate at infinity. proposed method based on high order element discretization combined with...