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We present a method for creating spacecraft-like data which can be used to train Machine Learning (ML) models to detect and classify structures in in-situ spacecraft data. First, we use the Grad-Shafranov (GS) equation to numerically solve for several magnetohydrostatic equilibria which are variations on a known analytic equilibrium. These equilibria are then used as the initial conditions for Particle-In-Cell (PIC) simulations in which the structures of interest are observed and labeled. We then take one-dimensional slices through the simulations to replicate what a spacecraft collecting data from the simulation would observe. This sliced data then can be used as training data for the initial training of ML models intended for use on spacecraft data. We demonstrate the method applied to the problem of detecting small-scale plasmoids in the magnetotail, which is important for understanding complex magnetotail reconnection dynamics. The simple 1D classifier we train is able to detect 77% of the plasmoid points in the dataset but also produces a large number of false positives. Our further work on this example problem is detailed, and further potential uses of the method are discussed.

We present the first statistical study of magnetic structures and associated energy dissipation observed during a single period of turbulent magnetic reconnection, by using the \textit{in-situ} measurements of the Magnetospheric Multiscale mission in the Earth's magnetotail on July 26, 2017. The structures are selected by identifying a bipolar signature in the magnetic field and categorized as plasmoids or current sheets via an automated algorithm which examines current density and plasma flow. The size of the plasmoids forms a decaying exponential distribution ranging from sub-electron up to ion scales. The presence of substantial number of current sheets is consistent with a physical picture of dynamic production and merging of plasmoids during turbulent reconnection. The magnetic structures are locations of significant energy dissipation via electric field parallel to the local magnetic field, while dissipation via perpendicular electric field dominates outside of the structures. Significant energy also returns from particles to fields., 17 pages, 3 figures, proofing version, accepted for publication in Geophysical Research Letters

The Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket experiment aims to investigate fundamental questions about the high-energy Sun through direct imaging and spectroscopy of hard X-rays. The experiment utilizes Wolter-I type nested hard X-ray mirrors and fine-pitch semiconductor detectors, which are separated by a 2m focal length. Tol date, FOXSI has had two successful flights, on 2012 November 02 and 2014 December 11, demonstrating that the technology can measure small-scale energy releases (microflares and aggregated nanoflares) from the solar corona. The third flight for FOXSI is scheduled for August 2018. Significant improvements have been made on the FOXSI instrumentation, including upgraded optic modules with more nested mirror shells; specially designed collimators to mitigate the number of single bounce photons (ie., ghost rays) reaching the focal plane detector; and fine-pitch double-sided CdTe strip detectors to replace some of the Si-based hard X-ray detectors for better efficiency for hard X-rays. Furthermore, a CMOS based soft X-ray (SXR) instrument, “Phoenix”, will be added to FOXSI-3 by replacing one hard X-ray detector with a photon-counting SXR sensor. This will enable evaluation of the Sun via imaging spectroscopy simultaneously over a large X-ray energy range covering soft to hard X-rays. This paper will describe the overall instrument design of the FOXSI-3 experiment, which will be sensitive to solar soft and hard X-rays in the 1 – 20 keV range, as well as give a summary of insightful results and lessons from the first two flights. Possible observations for FOXSI-3 will also be discussed.

The Experiment for X-ray Characterization and Timing (EXACT) mission will be a CubeSat based, hard X-ray spectrometer for measuring high-energy emission from solar flares with high time precision. Solar flares and the related coronal mass ejections affect space weather and the near-Earth environment through emission of solar energetic particles. Hard X-rays (HXRs) are emitted from flare-accelerated electrons, which are energized at or near the time of energy release, and therefore serve to probe the timing of energy release and particle acceleration. EXACT will study the hard X-rays generated by the Sun in the declining phase of Solar Cycle 24 in order to probe electron acceleration in flares and solar eruptive events while also serving as a precursor to future hard X-ray spectrometers that could monitor the Sun continuously. EXACT’s secondary mission is to demonstrate a spacecraft ranging technique based on timing of astrophysical X-ray and gamma ray bursts. EXACT will be a 3U (10x10x30 cm 3 ) CubeSat. This paper will discuss the scintillator detector under development for the mission, including the modeling of the detector response function, as well as expected observations of solar flares by EXACT.

The Focusing Optics X-ray Solar Imager (FOXSI) sounding rocket experiment conducts direct imaging and spectral observation of the Sun in hard X-rays, in the energy range 4 to 20 keV. These high-sensitivity observations are used to study particle acceleration and coronal heating. FOXSI is designed with seven grazing incidence optics modules that focus X-rays onto seven focal plane detectors kept at a 2m distance. FOXSI-1 was flown with seven Double-sided Si Strip Detectors (DSSD), and two of them were replaced with CdTe detectors for FOXSI-2. The upcoming FOXSI-3 flight will carry DSSD and CdTe detectors with upgraded optics for enhanced sensitivity. The detectors are calibrated using various radioactive sources. The detector’s spectral response matrix was constructed with diagonal elements using a Gaussian approximation with a spread (sigma) that accounts for the energy resolution of the detector. Spectroscopic studies of past FOXSI flight data suggest that the inclusion of lower energy X-rays could better constrain the spectral modeling to yield a more precise temperature estimation of the hot plasma. This motivates us to carry out an improved calibration to better understand the finer-order effects on the spectral response, especially at lower energies. Here we report our improved calibration of FOXSI detectors using experiments and Monte-Carlo simulations.