Mitzi Adams

Small-scale filament eruptions as the driver of X-ray jets in solar coronal holes

Solar X-ray jets are thought to be made by a burst of reconnection of closed magnetic field at the base of a jet with ambient open field. In the accepted version of the ‘emerging-flux’ model, such a reconnection occurs at a plasma current sheet between the open field and the emerging closed field, and also forms a localized X-ray brightening that is usually observed at the edge of the jet’s base. Here we report high-resolution X-ray and extreme-ultraviolet observations of 20 randomly selected X-ray jets that form in coronal holes at the Sun’s poles. In each jet, contrary to the emerging-flux model, a miniature version of the filament eruptions that initiate coronal mass ejections drives the jet-producing reconnection. The X-ray bright point occurs by reconnection of the ‘legs’ of the minifilament-carrying erupting closed field, analogous to the formation of solar flares in larger-scale eruptions. Previous observations have found that some jets are driven by base-field eruptions, but only one such study, of only one jet, provisionally questioned the emerging-flux model. Our observations support the view that solar filament eruptions are formed by a fundamental explosive magnetic process that occurs on a vast range of scales, from the biggest mass ejections and flare eruptions down to X-ray jets, and perhaps even down to smaller jets that may power coronal heating. A similar scenario has previously been suggested, but was inferred from different observations and based on a different origin of the erupting minifilament.

MgII Linear Polarization Measurements Using the MSFC Solar Ultraviolet Magnetograph

This paper will describe the Marshall Space Flight Centers Solar Ultraviolet Magnetograph (SUMI) sounding rocket program, with emphasis on the polarization characteristics of the VUV optics and their spectral, spatial and polarization resolution. SUMIs first flight (7/30/2010) met all of its mission success criteria and this paper will describe the data that was acquired with emphasis on the MgII linear polarization measurements.

A STUDY OF MAGNETIC COMPLEXITY USING HURST'S RESCALED RANGE ANALYSIS

A fractal analysis using the classical Hurst method has been applied to artificial data, simulated sunspot magnetic field data, and to data acquired with NASA/Marshall Space Flight Centers vector magnetograph. The main goals of this study are to quantify the complexity of an active region and to determine if significant changes in complexity are associated with flare activity. We tested the analysis using three basic types of two-dimensional synthetic data: (1) data composed of gaussians with various types of superimposed features, (2) random data, and (3) synthetic sunspots created from a basic, simple configuration on which are placed increasingly smaller structures. Our results confirm that the Hurst method of analysis is sensitive to the presence of large-scale structures within a two-dimensional image. When the large-scale structure has been removed, the value of the Hurst exponent is inversely proportional to increasing complexity in the image. The Hurst exponent of magnetograph data with the large-scale structure of the sunspot removed, shows a tantalizing variation in the shear parameter five minutes prior to a flare.

MgII observations using the MSFC solar ultraviolet magnetograph

This paper will describe the scientific goals of our sounding rocket program, the Solar Ultraviolet Magnetograph Investigation (SUMI). This paper will present a brief description of the optics that were developed to meet SUMIs scientific goals, discuss the spectral, spatial and polarization characteristics of SUMIs optics, describe SUMIs flight which was launched 7/30/2010, and discuss what we have learned from that flight.

Development of a polarimeter for magnetic field measurements in the ultraviolet

The polarizing optics that are being developed for the Solar UV Magnetograph Investigation (SUMI) are described. This polarimeter is being designed for a sounding rocket payload which will make simultaneous measurements of two magnetically sensitive lines CIV and MgII. With a limited observing program, the polarizing optics will be optimized for circular and linear polarization measurements in active regions. The Q polarization will represent exploratory measurements of the transverse field in strong sunspots. This paper will give a brief overview of the SUMI instrument and its scientific goals, will describe the polarimeter that will be used in the sounding rocket program, and will present some of the measurements that have been made on the SUMI polarization optics.

Evaluation of Two Fractal Methods for Magnetogram Image Analysis

Fractal and multifractal techniques have been applied to various types of solar data to study the fractal properties of sunspots as well as the distribution of photospheric magnetic fields and the role of random motions on the solar surface in this distribution. Other research includes the investigation of changes in the fractal dimension as an indicator for solar flares. Here we evaluate the efficacy of two methods for determining the fractal dimension of an image data set: the Differential Box Counting scheme and a new method, the Jaenisch scheme. To determine the sensitivity of the techniques to changes in image complexity, various types of constructed images are analyzed. In addition, we apply this method to solar magnetogram data from Marshall Space Flight Centers vector magnetograph.

A search for sunspot canopies using a vector magnetograph

Using a magnetograph, we examine four sunspots for evidence of a magnetic canopy at the penumbra/photosphere boundary. The penumbral edge is determined from the photometric intensity and is defined to correspond to the value of the average intensity minus twice the standard deviation from the average. From a comparison of the location of this boundary with the location of contours of the vertical and horizontal components of the magnetic field, we conclude that the data are best represented by canopy-type fields close to all four sunspots. There is some evidence that the magnetic inclination in the canopies is 5°–15° with respect to the horizontal and that the canopy base height lies in the middle/upper photosphere. The observations further suggest that the magnetic canopy of a sunspot begins at its outer penumbral boundary.

Development of a new vector magnetograph at Marshall Space Flight Center

This paper will describe a new vector magnetograph that has been developed at Marshall Space Flight Center. This magnetograph was a test ed for space flight concepts. One of those concepts that is currently being tested is the increased sensitivity to linear polarization by replacing electro-optical and rotating waveplates with a rotating linear analyzer. Our paper will describe the motivation for developing this magnetograph, compare this instrument with traditional magnetograph designs.

Optical Characteristics of the Marshall Space Flight Center Solar Ultraviolet Magnetograph

This paper will describe the scientific objectives of the Marshall Space Flight Center (MSFC) Solar Ultraviolet Magnetograph Investigation (SUMI) and the optical components that have been developed to meet those objectives. In order to test the scientific feasibility of measuring magnetic fields in the UV, a sounding rocket payload is being developed. This paper will discuss: (1) the scientific measurements that will be made by the SUMI sounding rocket program, (2) how the optics have been optimized for simultaneous measurements of two magnetic lines CIV (1550 Angstroms) and MgII (2800 Angstroms), and (3) the optical, reflectance, transmission and polarization measurements that have been made on the SUMI telescope mirrors and polarimeter.

A multifractal study of the scaling property of gamma-ray burst time profiles

Multifractal analyses have been proven successful in exposing scaling properties of experimental data. These methods of analysis have been applied to diverse areas of research including solar magnetic fields and dissipative fluid dynamics. Moreover, they are especially useful as algorithms for the detection of fully developed turbulence. In this preliminary paper we use the observed multiplier distribution, P(M), to directly calculate the f(α) function of gamma-ray burst time profiles. The results show the time-scaling properties of these profiles. At the very least, multifractal analyses should provide a better way to categorize GRB time profiles than currently exists. In the most-optimistic scenario, however, these algorithms could reveal fundamental physical properties of the underlying system(s) that produce the bursts.