Nitrogen Vacancy Center Optical Magnetometry of a Barium-Iron-Cobalt Superconductor

Experimentally probing the intrinsic properties of superconductors—such as the London penetration depth λ and the critical fields Hc1 and Hc2—poses a difficult task. Various sample- and measurement-related factors can impact the efficacy of results obtained for λ or Hc1, such as perturbations to the magnetic properties of a superconducting sample or crystalline defects. One measurement technique that can minimize the impact of both of these issues is known as Nitrogen Vacancy (NV) center magnetometry. In this work, we use NV center magnetometry to perform minimally-invasive measurements of the lower critical field Hc1 and the London penetration depth λ on a sample of Ba(Fe1−xCox)2As2, x = 7.4% (BaCo122)

The need for focused, hard X-ray investigations of the Sun

Understanding accelerated particles at the Sun is one of the most important problems in heliophysics. Flare-accelerated particles have huge energies; are an important source of particles in the heliosphere; and are the most important corollary to other areas of high-energy astrophysics. This paper describes the scientific motivation for X-ray studies of particle acceleration at the Sun

The need for focused, hard X-ray investigations of the Sun

Understanding the nature of energetic particles in the solar atmosphere is one of the most important outstanding problems in heliophysics. Flare-accelerated particles compose a huge fraction of the flare energy budget; they have large influences on how events develop; they are an important source of high-energy particles found in the heliosphere; and they are the single most important corollary to other areas of high-energy astrophysics. Despite the importance of this area of study, this topic has in the past decade received only a small fraction of the resources necessary for a full investigation. For example, NASA has selected no new Explorer-class instrument in the past two decades that is capable of examining this topic. The advances that are currently being made in understanding flare-accelerated electrons are largely undertaken with data from EOVSA (NSF), STIX (ESA), and NuSTAR (NASA Astrophysics). This is despite the inclusion in the previous Heliophysics decadal survey of the FOXSI concept as part of the SEE2020 mission, and also despite NASA's having invested heavily in readying the technology for such an instrument via four flights of the FOXSI sounding rocket experiment. Due to that investment, the instrumentation stands ready to implement a hard X-ray mission to investigate flare-accelerated electrons. This white paper describes the scientific motivation for why this venture should be undertaken soon.Comment: White paper submitted to the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033; 15 pages, 5 figure

The need for focused, hard X-ray investigations of the Sun

Understanding accelerated particles at the Sun is one of the most important problems in heliophysics. Flare-accelerated particles have huge energies; are an important source of particles in the heliosphere; and are the most important corollary to other areas of high-energy astrophysics. This paper describes the scientific motivation for X-ray studies of particle acceleration at the Sun

The physiology and pathophysiology of T-tubules in the heart

In cardiomyocytes, invaginations of the sarcolemmal membrane called t-tubules are critically important for triggering contraction by excitation-contraction (EC) coupling. These structures form functional junctions with the sarcoplasmic reticulum (SR), and thereby enable close contact between L-type Ca 2+ channels (LTCCs) and Ryanodine Receptors (RyRs). This arrangement in turn ensures efficient triggering of Ca 2+ release, and contraction. While new data indicate that t-tubules are capable of exhibiting compensatory remodeling, they are also widely reported to be structurally and functionally compromised during disease, resulting in disrupted Ca 2+ homeostasis, impaired systolic and/or diastolic function, and arrhythmogenesis. This review summarizes these findings, while highlighting an emerging appreciation of the distinct roles of t-tubules in the pathophysiology of heart failure with reduced and preserved ejection fraction (HFrEF and HFpEF). In this context, we review current understanding of the processes underlying t-tubule growth, maintenance, and degradation, underscoring the involvement of a variety of regulatory proteins, including junctophilin-2 (JPH2), amphiphysin-2 (BIN1), caveolin-3 (Cav3), and newer candidate proteins. Upstream regulation of t-tubule structure/function by cardiac workload and specifically ventricular wall stress is also discussed, alongside perspectives for novel strategies which may therapeutically target these mechanisms

Sunxspex: A High-energy Spectral Analysis Tool in Python

Sunxspex is a Python tool under development for the high-energy solar community to provide relevant spectral models and analyse observed data through forward-fitting and other methods. The community utilises several different spectral fitting tools; however, none can fit multiple spectra simultaneously with different fitting metrics while providing relevant models, being optimised for solar data products, and having a simple installation process. A software providing these features is desirable due to the increasing availability of solar observations from multiple instruments with the ability to investigate phenomena ranging over orders of magnitude. Sunxspex tackles these elements with a focus on community-led development. High-energy spectroscopic analysis involving forward-fitting has unique complications not faced in other disciplines. The process includes using physically driven models and a non-diagonal instrument-specific spectral response matrix to convert plasma parameters to a photon spectrum then to an instrument-modelled count spectrum which can finally be compared to the observed data. Therefore, converting from plasma parameters to instrument data is not a simple fitting process and requires a dedicated software package. Sunxspex must be agnostic to a range of data products from different instruments and different formats where the spectral data may be created from proprietary software, other python packages, or within Sunxspex itself. Sunxspex is also able to facilitate the inclusion of custom analytical tools and techniques which can be applied to the spectral data, such as MCMC analysis or other Bayesian methods

Magnetic Energy Powers the Corona: How We Can Understand its 3D Storage & Release

Synopsis 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 important problems. We advocate for new and multi-point co-optimized measurements, sensitive to magnetic field and other plasma parameters, spanning from optical to γ-ray wavelengths, to bring closure to these long-standing and fundamental questions. We discuss how our approach can fully describe the 3D magnetic field, embedded plasma, particle energization, and their joint evolution to achieve these objectives. Magnetic Energy Powers the Corona: How We Can Understand its 3D Storage & Releas