A5037450222- Solar and Space Plasma Dynamics
- Astro and Planetary Science
- Stellar, planetary, and galactic studies
- Ionosphere and magnetosphere dynamics
- Geomagnetism and Paleomagnetism Studies
- Geophysics and Gravity Measurements
- Pulmonary Hypertension Research and Treatments
- Solar Radiation and Photovoltaics
- Chronic Obstructive Pulmonary Disease (COPD) Research
- Astrophysics and Star Formation Studies
- Atmospheric Ozone and Climate
- Cardiac electrophysiology and arrhythmias
- Earthquake Detection and Analysis
- Cardiovascular and exercise physiology
- Cardiovascular Function and Risk Factors
- Astronomy and Astrophysical Research
- CCD and CMOS Imaging Sensors
- Cardiac, Anesthesia and Surgical Outcomes
- Gamma-ray bursts and supernovae
- Plasma Diagnostics and Applications
- Laser-induced spectroscopy and plasma
- Cardiac pacing and defibrillation studies
- Astronomical Observations and Instrumentation
- Optical Polarization and Ellipsometry
- Diabetic Foot Ulcer Assessment and Management
Lockheed Martin (United States)
2015-2024
NASA Research Park
2019-2023
University of Oslo
2014-2023
Bay Area Environmental Research Institute
2019-2023
Oslo University Hospital
1979-2020
Lockheed Martin (Canada)
2019
Smerteklinikken
2017
Military Medical Academy
2016
Shaheed Rajaei Cardiovascular Medical and Research Center
2012
University of Naples Federico II
2012
The Interface Region Imaging Spectrograph (IRIS) small explorer spacecraft provides simultaneous spectra and images of the photosphere, chromosphere, transition region, corona with 0.33-0.4 arcsec spatial resolution, 2 s temporal resolution 1 km/s velocity over a field-of-view up to 175 x arcsec. IRIS was launched into Sun-synchronous orbit on 27 June 2013 using Pegasus-XL rocket consists 19-cm UV telescope that feeds slit-based dual-bandpass imaging spectrograph. obtains in passbands from...
Alfvén waves have been invoked as a possible mechanism for the heating of Sun's outer atmosphere, or corona, to millions degrees and acceleration solar wind hundreds kilometers per second. However, sufficient strength not unambiguously observed in atmosphere. We used images high temporal spatial resolution obtained with Solar Optical Telescope onboard Japanese Hinode satellite reveal that chromosphere, region sandwiched between surface is permeated by strong amplitudes on order 10 25 second...
Context: Numerical simulations of stellar convection and photospheres have been developed to the point where detailed shapes observed spectral lines can be explained. Stellar atmospheres are very complex, different physical regimes present in zone, photosphere, chromosphere, transition region corona. To understand details atmosphere it is necessary simulate whole since layers interact strongly. These diverse takes a highly efficient massively parallel numerical code solve associated...
The solar corona is heated by jets of plasma propelled upward from the region immediately above Sun’s surface.
We use high-resolution observations of the Sun in Ca II H 3968 A from Solar Optical Telescope on Hinode to show that there are at least two types spicules dominate structure magnetic solar chromosphere. Both tied relentless magnetoconvective driving photosphere, but have very different dynamic properties. ``Type-I'' driven by shock waves form when global oscillations and convective flows leak into upper atmosphere along field lines 3-7 minute timescales. ``Type-II'' much more dynamic: they...
As the interface between Sun’s photosphere and corona, chromosphere transition region play a key role in formation acceleration of solar wind. Observations from Interface Region Imaging Spectrograph reveal prevalence intermittent small-scale jets with speeds 80 to 250 kilometers per second narrow bright network lanes this region. These have lifetimes 20 seconds widths ≤300 kilometers. They originate regions, often preceded by footpoint brightenings accompanied transverse waves amplitudes ~20...
The solar atmosphere was traditionally represented with a simple one-dimensional model. Over the past few decades, this paradigm shifted for chromosphere and corona that constitute outer atmosphere, which is now considered dynamic structured envelope. Recent observations by IRIS (Interface Region Imaging Spectrograph) reveal it difficult to determine what up down even in cool 6000-K photosphere just above surface: region hosts pockets of hot plasma transiently heated almost 100,000 K. energy...
The formation of jets such as dynamic fibrils, mottles, and spicules in the solar chromosphere is one most important, but also poorly understood, phenomena Sun's magnetized outer atmosphere. We use extremely high resolution observations from Swedish 1 m Solar Telescope combined with advanced numerical modeling to show that active regions these are a natural consequence upwardly propagating slow-mode magnetoacoustic shocks. These shocks form when waves generated by convective flows global...
We present unprecedented high-resolution Hα observations, obtained with the Swedish 1 m Solar Telescope, that, for first time, spatially and temporally resolve dynamic fibrils in active regions on Sun. These jetlike features are similar to mottles or spicules quiet find that most of these follow almost perfect parabolic paths their ascent descent. measure properties taken by 257 an overview deceleration, maximum velocity, length, duration, as well widths thickness a bright ring often occurs...
A prospective, randomised, double-blind study was performed to compare the effects of propranolol and placebo on sudden cardiac death in a high-risk group patients who survived acute myocardial infarction. Altogether 4929 with definite infarction were screened for inclusion: 574 (11.6%) died before randomisation, 3795 (77%) excluded. Five hundred sixty aged 35 70 years stratified into two risk groups randomly assigned treatment 40 mg four times day or placebo. Treatment started six days...
The Sun's corona is millions of degrees hotter than its 5000 K photosphere. This heating enigma typically addressed by invoking the deposition at coronal heights nonthermal energy generated interplay between convection and magnetic field near However, it remains unclear how where occurs filled with hot plasma. We show that cannot be only source revealing a significant mass supply mechanism driven from below, in chromosphere. quantify asymmetry spectral lines observed Hinode SOHO identify...
Spicules are long, thin, highly dynamic features that jut out ubiquitously from the solar limb. They dominate interface between chromosphere and corona may provide significant mass energy to corona. We use high-quality observations with Swedish 1-m Solar Telescope establish so-called type II spicules characterized by simultaneous action of three different types motion: 1. field-aligned flows order 50-100 km/s, 2. swaying motions 15-20 3. torsional 25-30 km/s. The first two modes have been...
The physical processes causing energy exchange between the Sun's hot corona and its cool lower atmosphere remain poorly understood. chromosphere transition region (TR) form an interface surface that is highly sensitive to coronal heating mechanism. High-resolution observations with Interface Region Imaging Spectrograph (IRIS) reveal rapid variability (~20 60 seconds) of intensity velocity on small spatial scales (≲500 kilometers) at footpoints dynamic loops. are consistent numerical...
In the lower solar atmosphere, chromosphere is permeated by jets known as spicules, in which plasma propelled at speeds of 50 to 150 kilometers per second into corona. The origin spicules poorly understood, although they are expected play a role heating million-degree corona and associated with Alfv\'enic waves that help drive wind. We compare magnetohydrodynamic simulations observations from Interface Region Imaging Spectrograph Swedish 1-m Solar Telescope. Spicules shown occur when...
ABSTRACT Aims To determine the prevalence of corrected QT interval (QTc) prolongation among patients in opioid maintenance treatment (OMT) and to investigate mortality potentially attributable QTc Norwegian OMT programme. Participants setting Two hundred Oslo were recruited assessment study between October 2006 August 2007. The register all receiving Norway (January 1997–December 2003) national death certificate used assess mortality. Mortality records examined for 90 deaths that had...
We present the implementation of a radiative transfer solver with coherent scattering in new BIFROST code for magneto-hydrodynamical (MHD) simulations stellar surface convection. The is fully parallelized using MPI domain decomposition, which allows large grid sizes and improved resolution hydrodynamical structures. apply to simulate granulation solar-type star, ignoring magnetic fields, investigate importance atmospheric structure. A term added equation, requiring an iterative computation...
Emission lines formed in the transition region (TR) of Sun have long been known to show pervasive redshifts. Despite a variety proposed explanations, these TR downflows (and slight upflows low corona) remain poorly understood. We present results from comprehensive three-dimensional MHD models that span upper convection zone up corona, 15 Mm above photosphere. The and coronal heating is caused by stressing magnetic field photospheric "zone dynamics," but also some injection emerging flux....
The solar chromosphere and transition region (TR) form an interface between the Sun's surface its hot outer atmosphere. There, most of nonthermal energy that powers atmosphere is transformed into heat, although detailed mechanism remains elusive. High-resolution (0.33-arc second) observations with NASA's Interface Region Imaging Spectrograph (IRIS) reveal a TR are replete twist or torsional motions on sub-arc second scales, occurring in active regions, quiet Sun coronal holes alike. We...