scholarly journals Comparative Study of Electric Currents and Energetic Particle Fluxes in a Solar Flare and Earth Magnetospheric Substorm

2021 ◽  
Vol 923 (2) ◽  
pp. 151
Author(s):  
Anton Artemyev ◽  
Ivan Zimovets ◽  
Ivan Sharykin ◽  
Yukitoshi Nishimura ◽  
Cooper Downs ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Flare ◽  
Energy Release ◽  
Energetic Particle ◽  
Current System ◽  
Data Sets ◽  
Magnetospheric Substorms ◽  
X Ray ◽  
Particle Fluxes

Abstract Magnetic field line reconnection is a universal plasma process responsible for the conversion of magnetic field energy to plasma heating and charged particle acceleration. Solar flares and Earth's magnetospheric substorms are two of the most investigated dynamical systems where global magnetic field reconfiguration is accompanied by energization of plasma populations. Such a reconfiguration includes formation of a long-living current system connecting the primary energy release region and cold dense conductive plasma of the photosphere/ionosphere. In both flares and substorms the evolution of this current system correlates with the formation and dynamics of energetic particle fluxes (although energy ranges can be different for these systems). Our study is focused on the similarity between flares and substorms. Using a wide range of data sets available for flare and substorm investigations, we qualitatively compare the dynamics of currents and energetic particle fluxes for one flare and one substorm. We show that there is a clear correlation between energetic particle precipitations (associated with energy release due to magnetic reconnection seen from riometer and hard X-ray measurements) and magnetic field reconfiguration/formation of the current system, whereas the long-term current system evolution correlates better with hot plasma fluxes (seen from in situ and soft X-ray measurements). We then discuss how data sets of in situ measurements of magnetospheric substorms can help interpret solar flare data.

scholarly journals In-situ diffraction experiments at the Photon Factory MX beamlines

2014 ◽  
Vol 70 (a1) ◽  
pp. C500-C500
Author(s):  
Yusuke Yamada ◽  
Naohiro Matsugaki ◽  
Masahiko Hiraki ◽  
Ryuichi Kato ◽  
Toshiya Senda
Keyword(s):  
Gas Flow ◽  
Active Area ◽  
Array Detector ◽  
Data Sets ◽  
Diffraction Experiment ◽  
X Ray ◽  
Photon Factory ◽  
Large Active Area ◽  
In Situ Diffraction

Crystallization trial is one of the most important but time-consuming steps in macromolecular crystallography. Once a crystal appears in a certain crystallization condition, the crystal is typically harvested from the crystallization drop, soaked into a cryoprotection buffer, flash-cooled with a liquid nitrogen or cold gas flow and finally evaluated its diffraction quality by an X-ray beam. During these long process, crystal may be damaged and the result from the diffraction experiment does not necessarily reflect a nature of the crystal. On in-situ diffraction experiment, where a crystal in a crystallization drop is directly irradiated to an X-ray beam, a diffraction image from a crystal without any external factors such as harvesting and cryoprotection and, as a result, a nature of crystal can be evaluated quickly. In the Photon Factory, a new table-top diffractometer for in-situ diffraction experiments has been developed. It consists of XYZ translation stages with a plate handler, on-axis viewing system with a large numeric aperture and a plate rack where ten crystallization plates can be placed. These components sit on a common plate and it is placed on the existing diffractometer table in the beamline endstation. The CCD detector with a large active area and a pixel array detector with a small active area are used for acquiring diffraction images from crystals. Dedicated control software and user interface were also developed. Since 2014, user operation of the new diffractometer was started and in-situ diffraction experiments were mainly performed for evaluations of crystallization plates from a large crystallization screening project in our facility. BL-17A [1], one of micro-focus beamlines at the Photon Factory, is planned to be upgraded in March 2015. With this upgrade, a new diffractometer, which has a capability to handle a crystallization plate, will be installed so that diffraction data sets from crystals in crystallization drop can be collected.

SGTools: a suite of tools for processing and analyzing large data sets from in situ X-ray scattering experiments

2022 ◽  
Vol 55 (1) ◽  
Author(s):  
Nie Zhao ◽  
Chunming Yang ◽  
Fenggang Bian ◽  
Daoyou Guo ◽  
Xiaoping Ouyang
Keyword(s):  
Data Processing ◽  
Small Angle ◽  
Large Data ◽  
Large Data Sets ◽  
Data Sets ◽  
X Ray ◽  
Intensity Mapping ◽  
X Ray Scattering ◽  
Ray Scattering

In situ synchrotron small-angle X-ray scattering (SAXS) is a powerful tool for studying dynamic processes during material preparation and application. The processing and analysis of large data sets generated from in situ X-ray scattering experiments are often tedious and time consuming. However, data processing software for in situ experiments is relatively rare, especially for grazing-incidence small-angle X-ray scattering (GISAXS). This article presents an open-source software suite (SGTools) to perform data processing and analysis for SAXS and GISAXS experiments. The processing modules in this software include (i) raw data calibration and background correction; (ii) data reduction by multiple methods; (iii) animation generation and intensity mapping for in situ X-ray scattering experiments; and (iv) further data analysis for the sample with an order degree and interface correlation. This article provides the main features and framework of SGTools. The workflow of the software is also elucidated to allow users to develop new features. Three examples are demonstrated to illustrate the use of SGTools for dealing with SAXS and GISAXS data. Finally, the limitations and future features of the software are also discussed.

scholarly journals Jets in the soft state in Cyg X-3 caused by advection of the donor magnetic field and unification with low-mass X-ray binaries

2019 ◽  
Vol 492 (1) ◽  
pp. 223-231 ◽  
Author(s):  
Xinwu Cao ◽  
Andrzej A Zdziarski
Keyword(s):  
Magnetic Field ◽  
High Mass ◽  
Vertical Magnetic Field ◽  
Subsequent Formation ◽  
X Ray ◽  
Soft State ◽  
Hard State ◽  
Low Mass ◽  
X Ray Binaries

ABSTRACT The high-mass accreting binary Cyg X-3 is distinctly different from low-mass X-ray binaries (LMXBs) in having powerful radio and γ-ray emitting jets in its soft spectral state. However, the transition from the hard state to the soft one is first associated with quenching of the hard-state radio emission, as in LMXBs. The powerful soft-state jets in Cyg X-3 form, on average, ∼50 d later. We interpret the initial jet quenching as due to the hard-state vertical magnetic field quickly diffusing away in the thin disc extending to the innermost stable circular orbit in the soft state, or, if that field is produced in situ, also cessation of its generation. The subsequent formation of the powerful jets occurs due to advection of the magnetic field from the donor. We find this happens only above certain threshold accretion rate associated with appearance of magnetically driven outflows. The ∼50 d lag is of the order of the viscous time-scale in the outer disc, while the field advection is much faster. This process does not happen in LMXBs due to the magnetic fluxes available from their donors being lower than that for the wind accretion from the Wolf–Rayet donor of Cyg X-3. In our model, the vertical magnetic field in the hard state, required to form the jets both in Cyg X-3 and LMXBs, is formed in situ rather than advected from the donor. Our results provide a unified scenario of the soft and hard states in both Cyg X-3 and LMXBs.

The Tearing Mode Instability in a Partially Ionized Plasma

1979 ◽  
Vol 3 (6) ◽  
pp. 367-368 ◽  
Author(s):  
N. F. Cramer ◽  
I. J. Donnelly
Keyword(s):  
Magnetic Field ◽  
Star Formation ◽  
Solar Flare ◽  
Experimental Evidence ◽  
Energy Release ◽  
Release Mechanism ◽  
Tearing Mode ◽  
Mode Instability ◽  
Laboratory Plasma ◽  
Tearing Instability

The resistive tearing mode instability is a mechanism that in some cases will render unstable a magnetohydrodynamic equilibrium of a plasma that is ideally stable, i.e. stable if no dissipative oiesses are taken into account. There is much experimental evidence that this instability is the cause of the current disruptions observed in laboratory plasma devices (von Goeler et al. 1974). In the astrophysical context, the instability has been invoked in connection with the solar flare energy release mechanism (Coppi and Friedland 1971) and the problem of the disconnection of the protostar matter from the interstellar magnetic field during star formation (Mestel 1966). In the latter problem the tearing instability gives rise to a much smaller timescale for magnetic reconnection than does ordinary resistive diffusion.

scholarly journals Evidence for Particle Acceleration During Magnetospheric Substorms

1994 ◽  
Vol 142 ◽  
pp. 531-539
Author(s):  
Ramon E. Lopez ◽  
Daniel N. Baker
Keyword(s):  
Solar Wind ◽  
Particle Acceleration ◽  
Energy Release ◽  
Acceleration Of Particles ◽  
Magnetospheric Substorms ◽  
Geomagnetic Tail ◽  
Dissipation Of Energy ◽  
In Situ Observations ◽  
Current Systems

AbstractMagnetospheric substorms represent the episodic dissipation of energy stored in the geomagnetic tail that was previously extracted from the solar wind. This energy release produces activity throughout the entire magnetosphere-ionosphere system, and it results in a wide variety of phenomena such as auroral intensifications and the generation of new current systems. All of these phenomena involve the acceleration of particles, sometimes up to several MeV. In this paper we present a brief overview of substorm phenomenology. We then review some of the evidence for particle acceleration in Earth’s magnetosphere during substorms. Such in situ observations in this most accessible of all cosmic plasma domains may hold important clues to understanding acceleration processes in more distant astrophysical systems.Subject headings: acceleration of particles — Earth — solar wind

Initial signatures of magnetic field and energetic particle fluxes at tail Reconfiguration: Explosive growth phase

1992 ◽  
Vol 97 (A12) ◽  
pp. 19311 ◽  
Author(s):  
S. Ohtani ◽  
K. Takahashi ◽  
L. J. Zanetti ◽  
T. A. Potemra ◽  
R. W. McEntire ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Growth Phase ◽  
Energetic Particle ◽  
Particle Fluxes

scholarly journals Forecasting Solar Energetic Particle (SEP) events with Flare X-ray peak ratios

2018 ◽  
Vol 8 ◽  
pp. A47 ◽  
Author(s):  
Stephen W. Kahler ◽  
Alan. G. Ling
Keyword(s):  
Solar Flare ◽  
Space Weather ◽  
Coronal Mass Ejections ◽  
Energetic Particle ◽  
Solar Energetic Particle ◽  
Western Hemisphere ◽  
X Rays ◽  
X Ray ◽  
Forecasting Methods ◽  
Versus Peak

Solar flare X-ray peak fluxes and fluences in the 0.1–0.8 nm band are often used in models to forecast solar energetic particle (SEP) events. Garcia (2004) [Forecasting methods for occurrence and magnitude of proton storms with solar soft X rays, Space Weather, 2, S02002, 2004] used ratios of the 0.05–0.4 and 0.1–0.8 nm bands of the X-ray instrument on the GOES spacecraft to plot inferred peak flare temperatures versus peak 0.1–0.8 nm fluxes for flares from 1988 to 2002. Flares associated with E > 10 MeV SEP events of >10 proton flux units (pfu) had statistically lower peak temperatures than those without SEP events and therefore offered a possible empirical forecasting tool for SEP events. We review the soft and hard X-ray flare spectral variations as SEP event forecast tools and repeat Garcia’s work for the period 1998–2016, comparing both the peak ratios and the ratios of the preceding 0.05–0.4 nm peak fluxes to the later 0.1–0.8 nm peak fluxes of flares >M3 to the occurrence of associated SEP events. We divide the events into eastern and western hemisphere sources and compare both small (1.2–10 pfu) and large (≥300 pfu) SEP events with those of >10 pfu. In the western hemisphere X-ray peak ratios are statistically lower for >10 pfu SEP events than for non-SEP events and are even lower for the large (>300 pfu) events. The small SEP events, however, are not distinguished from the non-SEP events. We discuss the possible connections between the flare X-ray peak ratios and associated coronal mass ejections that are presumed to be the sources of the SEPs.

In Situ Diffraction Studies: Thermal Decomposition of a Natural Plumbojarosite and the Development of Rietveld-Based Data Analysis Techniques

2010 ◽  
Vol 651 ◽  
pp. 37-64 ◽  
Author(s):  
Ian C. Madsen ◽  
Ian E. Grey ◽  
Stuart J. Mills
Keyword(s):  
Thermal Decomposition ◽  
Amorphous Material ◽  
Data Sets ◽  
X Ray Diffraction ◽  
Data Set ◽  
X Ray ◽  
Analysis Techniques ◽  
Path Lengths ◽  
Instrument Configuration

A study of the thermal decomposition sequence of a sample of natural arsenian plumbojarosite has been undertaken using in situ X-ray diffraction. The sample was heated to 900°C using an Anton-Paar heating stage fitted to an INEL CPS120 diffractometer. The data were analysed using a whole-pattern, Rietveld based approach for the extraction of quantitative phase abundances. The instrument configuration used required the development and application of algorithms to correct for aberrations in the (i) peak intensities due to differing path lengths of incident and diffracted beams in the sample and (ii) peak positions due to sample displacement. Details of the structural models used were refined at selected steps in the pattern and then fixed for subsequent analysis. The data sequence consists of some 110 individual data sets which were analysed sequentially with the output of each run forming the input for analysis of the next data set. The results of the analysis show a complex breakdown and recrystallisation sequence including the formation of a major amount of amorphous material after initial breakdown of the plumbojarosite.

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