Year: 2020
Type: article
Abstract: We describe a new algorithm for reconstruction of differential emission measures (DEMs) in the solar corona. Although a number of such algorithms currently exist, they can have difficulty converging for some cases and can be complex, slow, or idiosyncratic in their output (i.e., their inversions can have features that are a result of the inversion code and instrument response, not of the solar source); we will document some of these issues in this paper. The new algorithm described here significantly reduces these drawbacks and is particularly notable for its simplicity; it is reproduced here, in full, on a single page. After we describe the algorithm, we compare its performance and fidelity with some prevalent methods. Although presented here for extreme-ultraviolet data, the algorithm is robust and extensible to any other wavelengths (e.g., X-rays) where the DEM treatment is valid.
Source: The Astrophysical Journal
Authors: Joseph Plowman, Amir Caspi
Institutions: National Solar Observatory, Southwest Research Institute
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: bronze
Awards: LARGE REGIONS OF CORONAL DIMMING OFTEN ACCOMPANY CORONAL MASS EJECTIONS CMES. THE DIMMINGS DEVELOP DURING OR SOON AFTER THE ERUPTION, AND MAY TRACE F, GOALS&OBJECTIVES: WE SEEK TO UNDERSTAND WHETHER THE 'NANOFLARE HYPOTHESIS CAN EXPLAIN CORONAL HEATING BY ANALYZING NEW HIGH QUALITY EMPIRICAL DATA AND BY UNDERSTANDING THOSE DATA USING BOTH THEORY AND FORWARD MODELING. DESPITE SEVERAL IMPORTANT STUDIES OVER THE PAST TWO DECADES IT IS NOT YET CLEAR WHETHER THE SMALLEST SCALE EVENTS DELIVER MORE OR LESS POWER TO THE CORONA THAN DO SOLAR FLARES THEMSELVES. THE NUMBER VS. ENERGY DISTRIBUTION OF ENERGETIC EVENTS IS A POWER LAW WHOSE EXPONENT IS TANTALIZINGLY CLOSE TO THE CRITICAL VALUE OF -2. EXACTLY WHERE THE EXPONENT LANDS HAS NOT BEEN CONCLUSIVELY DETERMINED HOWEVER AND THE POWER LAW MAY CHANGE AT THE SMALLEST SCALES (HERE NOISE EFFECTS DOMINATE EXISTING STUDIES SO THEORETICAL ESTIMATES HAVE EXTRAPOLATED FROM LARGER SCALES). WE WILL FOCUS ON THE DISTRIBUTIONS OF THE SMALLEST IMPULSIVE EVENTS VISIBLE WITH SDO/AIA WHICH OFFERS GREATLY IMPROVED SENSITIVITY CADENCE TEMPERATURE COVERAGE AND FOV COMPARED TO PRIOR WORK USING TRACE. THE PROPERTIES OF EACH DETECTED EVENT WILL BE CAREFULLY CATALOGUED USING DIFFERENTIAL EMISSION MEASURE (DEM) ANALYSIS TO INFER TEMPERATURES AND ENERGETICS. IN TANDEM WITH THE AIA DATA ANALYSIS WE WILL CARRY OUT 'SYNTHETIC DATA' ANALYSIS EXERCISES AND FORWARD FITTING USING THE EBTEL AND/OR HYDRAD NUMERICAL MODELS TO IDENTIFY AND CORRECT FOR SYSTEMATIC CROSS-SCALE BIAS IN THE DETECTION ALGORITHMS. OUR MODELING COMPONENT IS A CRITICAL INNOVATION BECAUSE IT ALLOWS US TO UNDERSTAND AND CORRECT SYSTEMATIC SAMPLING EFFECTS THAT COULD SKEW THE SMALL-SCALE TAIL OF THE DISTRIBUTION. THESE EFFECTS INCLUDE BOTH SAMPLING BIAS AND PHYSICAL EFFECTS THAT AFFECT DETECTABILITY OF INDIVIDUAL EVENTS., G3258293986, SOLAR FLARES ARE THE MOST POWERFUL EXPLOSIONS IN THE SOLAR SYSTEM, RELEASING 1032 1033 ERGS OVER TIMESCALES OF ONLY 102 103 SECONDS. A SIGNIFICANT FR, THE RESPONSE OF THE ATMOSPHERE TO IMPULSIVE SOLAR EVENTS (RAISE) TARGETED SCIENCE TEAM WILL COMPREHENSIVELY ADDRESS THE FOCUSED SCIENCE TOPIC SHORT
OpenAlex ID: W3035157015