Adam Kobelski

University of Alabama in Huntsville | UAH · Center for Space Plasma and Aeronomic Research (CSPAR)

The middle corona, the region roughly spanning heliocentric altitudes from 1.5–6 R⊙, encompasses almost all of the influential physical transitions and processes that govern the behavior of coronal outflow into the heliosphere. Eruptions that could disrupt the near-Earth environment propagate through it. Importantly, it also modulates inflow from a...

Solar flares and the often associated solar eruptive events serve as an outstanding laboratory to study the magnetic reconnection and the associated energy release and conversion processes under plasma conditions difficult to reproduce in the laboratory, and with considerable spatiotemporal details not possible elsewhere in the universe. In the pas...

The “middle corona,” defined by West et al. (2022) as the region between ∼1.5–6 R⊙, is a critical transition region that connects the highly structured lower corona to the outer corona where the magnetic field becomes predominantly radial. At radio wavelengths, remote-sensing of the middle corona falls in the meter–decameter wavelength range where...

Heliophysics image data largely relies on a forty-year-old ecosystem built on the venerable Flexible Image Transport System (FITS) data standard. While many in situ measurements use newer standards, they are difficult to integrate with multiple data streams required to develop global understanding. Additionally, most data users still engage with da...

The coronal magnetic field is the prime driver behind many as-yet unsolved mysteries: solar eruptions, coronal heating, and the solar wind, to name a few. It is, however, still poorly observed and understood. We highlight key questions related to magnetic energy storage, release, and transport in the solar corona, and their relationship to these im...

The middle corona, the region roughly spanning heliocentric distances from 1.5 to 6 solar radii, encompasses almost all of the influential physical transitions and processes that govern the behavior of coronal outflow into the heliosphere. The solar wind, eruptions, and flows pass through the region, and they are shaped by it. Importantly, the regi...

The "middle corona," defined by West et al. (2022) as the region between ~1.5-6 solar radii, is a critical transition region that connects the highly structured lower corona to the outer corona where the magnetic field becomes predominantly radial. At radio wavelengths, remote-sensing of the middle corona falls in the meter-decameter wavelength ran...

The strongest known correspondence between ALMA 3mm emission and other solar observations is between the H-alpha line width and 3 mm brightness temperature, while the typical 3-5min p-mode oscillations found in many chromospheric diagnostics are often lacking from ALMA Band 3 and 6 observations. We study these issues using a publicly available data...

The middle corona, the region roughly spanning heliocentric altitudes from $1.5$ to $6\,R_\odot$, encompasses almost all of the influential physical transitions and processes that govern the behavior of coronal outflow into the heliosphere. Eruptions that could disrupt the near-Earth environment propagate through it. Importantly, it modulates inflo...

New instruments sensitive to chromospheric radiation at X-ray, UV, visible, IR, and submillimeter wavelengths have become available that significantly enhance our ability to understand the bidirectional flow of energy through the chromosphere. We describe the calibration, coalignment, initial results, and public release of a new data set combining...

New instruments sensitive to chromospheric radiation at X-ray, UV, Visible, IR, and sub-mm wavelengths have become available that significantly enhance our ability to understand the bi-directional flow of energy through the chromosphere. We describe the calibration, co-alignment, initial results, and public release of a new data set combining a lar...

In this work we use solar observations with the ALMA radio telescope at the wavelength of 1.21 mm. The aim of the analysis is to improve understanding of the solar chromosphere, a dynamic layer in the solar atmosphere between the photosphere and corona. The study has an observational and a modeling part. In the observational part full-disc solar im...

Context. Various solar features can be seen in emission or absorption on maps of the Sun in the millimetre and submillimetre wavelength range. The recently installed Atacama Large Millimetre/submillimetre Array (ALMA) is capable of observing the Sun in that wavelength range with an unprecedented spatial, temporal and spectral resolution. To interpr...

Observations of the Sun at millimeter and submillimeter wavelengths offer a unique probe into the structure, dynamics, and heating of the chromosphere; the structure of sunspots; the formation and eruption of prominences and filaments; and energetic phenomena such as jets and flares. High-resolution observations of the Sun at millimeter and submill...

The Atacama Large Millimeter-submillimeter Array (ALMA) radio telescope has commenced science observations of the Sun starting in late 2016. Since the Sun is much larger than the field of view of individual ALMA dishes, the ALMA interferometer is unable to measure the background level of solar emission when observing the solar disk. The absolute te...

The VEGAS multi-beam spectrometer (VEGAS) was built for the Green Bank Telescope (GBT) through a partnership between the National Radio Astronomy Observatory (NRAO) and the University of California at Berkeley. VEGAS is based on a Field Programmable Gate Array (FPGA) frontend and a heterogeneous computing backend comprised of Graphical Processing U...

Small scale flare-like brightenings around active regions are among the smallest and most fundamental of energetic transient events in the corona, providing a testbed for models of heating and active region dynamics. In a previous study, we modeled a large collection of these microflares observed with Hinode/XRT using EBTEL and found that they requ...

Strong evidence exists that coronal loops as observed in EUV and soft X-rays may not be monolithic isotropic structures, but can often be more accurately modeled as bundles of independent strands. Modeling the observed active region transient brightenings (ARTBs) within this framework allows exploration of the energetic ramifications and characteri...

The X-Ray Telescope (XRT) onboard the Hinode satellite, launched 23 September 2006 by the Japanese Aerospace Exploration Agency (JAXA) is a joint mission between Japan, the United States, and the United Kingdom to study the solar corona. In particular XRT was designed to study solar plasmas with temperatures between 1 and 10 MK with $\approx1''$ pi...

On May 9, 2012, the the straylight level of XRT on Hinode suddenly increased, consistent with the appearance of a pinhole in the entrance filter (possibly a micrometeorite breach). The effect of this event is most noticeable in the optical G band data, which shows an average light excess of ~30%. However, data in several of the X-ray filters is als...

We have developed estimates of the systematic uncertainties for the X-Ray Telescope (XRT) on Hinode. These estimates are included as optional returns from the standard XRT data reduction software, xrt_prep.pro. Included in these software estimates are uncertainties from instrument vignetting, dark current subtraction, split bias leveling, Fourier f...

Strong evidence currently exists that coronal loops as observed in EUVs and soft X-rays are not monolithic structures, but actually exist as bundles of independent strands. It is of significant importance to determine the size and number density of these strands in order to better understand the spatial and temporal scales of magnetic reconnection...

We calculated the Hinode/XRT temperature response functions with different assumptions of elemental abundances. The enhancement of the low FIP elements significantly affects the amplitude of the XRT response curves. This yields a significant difference in the emission measures calculated from the filter ratio method, while the effect on derived tem...

We have developed estimates of the systematic photometric uncertainties the X-Ray Telescope (Kano et al. (2008)) on Hinode (Kosugi et al.(2007)). These estimates are included as optional returns from the standard XRT data reduction software, xrt_prep.pro. Included in the software estimates are uncertainties from instrument vignetting, dark current...

The apparent width of observed coronal loops can have significant effects on the perceived evolution of flaring active regions. Frequently, comparing a model flare to observation requires an estimate of the filling factor of loops contributing to the signal. If the analysis assumes the loops are resolved, the cooling times derived from the observat...

In the impulsive phase of solar flares the primary source of plasma heating is collisions between the nonthermal particles and the ambient, thermal plasma in the flare loop. Thus the thermal emission (e.g., soft X-rays) can yield clues to the properties of the nonthermal beam. We have undertaken a study of the nonthermal particle signatures contain...

Much work has been done in characterizing the nonthermal particle beams found in flares. Most of this work has concentrated on the interpretation of hard X-ray (HXR) emission. While HXR emission does have a direct connection to the nonthermal particle beam, there are other emission mechanisms that can also provide insight into the nature of the non...

With the impressive amount of data that have poured out from Chandra and XMM/Newton X-ray space missions, as well as the lower energy band observations, we are now in the position where careful comparison of neutron star thermal evolution theories with observations will help us to distinguish among various competing theories. For instance, the late...

We present multi-color transformations and photometric parallaxes for a sample of 40 low mass dwarfs selected from the Sloan Digital Sky Survey (SDSS) and the General Catalog of Trigonometric Stellar Parallaxes. Our sample was re-observed at the Manastash Ridge Observatory (MRO) using both Sloan and Johnson-Cousin filters and color transformations...