Track membranes with open pores used as diffractive filters for space-based x-ray and EUV solar observations

2009 ◽  
Vol 48 (5) ◽  
pp. 834 ◽  
Author(s):  
Marie Dominique ◽  
A. V. Mitrofanov ◽  
J.-F. Hochedez ◽  
P. Yu. Apel ◽  
U. Schühle ◽  
...  
Keyword(s):  
X Ray ◽  
Solar Observations ◽  
Track Membranes

scholarly journals Stellar activity and coronal heating: an overview of recent results

2015 ◽  
Vol 373 (2042) ◽  
pp. 20140259 ◽  
Author(s):  
Paola Testa ◽  
Steven H. Saar ◽  
Jeremy J. Drake
Keyword(s):  
Magnetic Activity ◽  
Coronal Heating ◽  
Complementary Information ◽  
Stellar Activity ◽  
X Ray ◽  
Solar Observations ◽  
Term Evolution ◽  
Wide Range ◽  
Stellar Magnetic Fields

Observations of the coronae of the Sun and of solar-like stars provide complementary information to advance our understanding of stellar magnetic activity, and of the processes leading to the heating of their outer atmospheres. While solar observations allow us to study the corona at high spatial and temporal resolution, the study of stellar coronae allows us to probe stellar activity over a wide range of ages and stellar parameters. Stellar studies therefore provide us with additional tools for understanding coronal heating processes, as well as the long-term evolution of solar X-ray activity. We discuss how recent studies of stellar magnetic fields and coronae contribute to our understanding of the phenomenon of activity and coronal heating in late-type stars.

scholarly journals The Needs and Requirements from the Standpoint of the Ultraviolet Solar Observations

1968 ◽  
Vol 1 ◽  
pp. 538-540
Author(s):  
E.M. Reeves
Keyword(s):  
Spatial Resolution ◽  
Time Resolution ◽  
Solar Disk ◽  
Emission Lines ◽  
High Time Resolution ◽  
The Sun ◽  
X Ray ◽  
Solar Observations ◽  
Partial Success

Extending from the present to the early part of 1969 there are three Orbiting Solar Observatories to be launched, and these will all be capable of constructing spectroheliograms of the Sun in solar emission lines of the EUV and X-ray region. The recently launched and highly successful OSO-III has obtained EUV and X-ray spectra with high-time resolution, but without spatial resolution on the solar disk. The later OSO satellites will provide spatial resolution of 1′ of arc to 30″ of arc, and will provide the basis for the extension to even higher spatial resolution in the future.The comparatively short periods covered by these satellites, coupled with a real probability of only partial success, make it particularly important to obtain the fullest possible use of the data by implementing a complementary and simultaneous series of ground-based observations.

scholarly journals Observations of stellar coronae

1987 ◽  
Vol 122 ◽  
pp. 333-345 ◽  
Author(s):  
G. S. Vaiana ◽  
S. Sciortino
Keyword(s):  
Magnetic Field ◽  
Unsolved Problem ◽  
Evolutionary Stage ◽  
Related Activity ◽  
Coronal Emission ◽  
X Ray ◽  
Surface Magnetic Field ◽  
Solar Observations ◽  
Field Activity ◽  
Early Type Stars

We present an overview of recent stellar X-ray observations, with some discussion of the requirements for future observations. We argue that solar observations indicate that coronal X-ray emission is strongly related to surface magnetic field activity; we show that the interpretation of X-ray stellar coronal emission from late-type stars within the framework of models analogous to those developed for the solar corona is viable, and it is supported by many experimental results. The extension of this solar analogy to the early-type stars is quite questionable and remains an unsolved problem, while the working hypothesis of an X-ray phase, related to phenomena of magnetic field-related activity, as contrasted to a wind phase during the PMS evolutionary stage is suggested by the present status of observations.

VI. The Sun as a Star

1988 ◽  
Vol 20 (1) ◽  
pp. 102-106
Author(s):  
L.E. Cram
Keyword(s):  
Time Scales ◽  
Spatial Extent ◽  
The Sun ◽  
Distinguishing Characteristic ◽  
X Ray ◽  
Spatially Resolved ◽  
Solar Observations ◽  
The Earth ◽  
The Subject

Studies of the global (spatially unresolved) output from the sun are important for two main reasons: (1) the global solar output directed towards the earth plays a central role in solar-terrestrial relations, and (2) global solar observations form a link between (neccessarily) global observations of stars and the more refined spatially resolved observations which are available for the sun. This report covers both aspects (insofar as they concern the sun), using the time-scales of various phenomena as a basic distinguishing characteristic. Note that certain studies of spatially unresolved solar output have not been discussed, since they are actually directed toward the investigation of phenomena of strictly limited spatial extent [e.g. radiospectrograph observations (e.g. Wiehl et al. 1985) and studies of X-ray bursts (e.g. Thomas et al. 1985)]. Collections of relevant papers may be found in De Jager and Svestka (1985) and Labonte et al. (1984), while a review of germane stellar work is available in Baliunas and Vaughan (1985) and solar-terrestrial work in Donnelly and Heath (1985). A comprehensive summary of the subject by Hudson will appear soon in Review of Geophysics and Planetary Physics.

scholarly journals High-speed X-ray imaging spectroscopy system with Zynq SoC for solar observations

2018 ◽  
Vol 912 ◽  
pp. 191-194 ◽  
Author(s):  
Shin-nosuke Ishikawa ◽  
Tadayuki Takahashi ◽  
Shin Watanabe ◽  
Noriyuki Narukage ◽  
Satoshi Miyazaki ◽  
...  
Keyword(s):  
High Speed ◽  
Imaging Spectroscopy ◽  
X Ray ◽  
Solar Observations ◽  
X Ray Imaging ◽  
Spectroscopy System

scholarly journals Conformal SiO2 coating of sub-100 nm diameter channels of polycarbonate etched ion-track channels by atomic layer deposition

2015 ◽  
Vol 6 ◽  
pp. 472-479 ◽  
Author(s):  
Nicolas Sobel ◽  
Christian Hess ◽  
Manuela Lukas ◽  
Anne Spende ◽  
Bernd Stühn ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
Stoichiometric Composition ◽  
Atomic Layer ◽  
X Ray ◽  
X Ray Scattering ◽  
Layer Deposition ◽  
Track Membranes ◽  
Cylindrical Tubes ◽  
Coated Membranes

Polycarbonate etched ion-track membranes with about 30 µm long and 50 nm wide cylindrical channels were conformally coated with SiO2 by atomic layer deposition (ALD). The process was performed at 50 °C to avoid thermal damage to the polymer membrane. Analysis of the coated membranes by small angle X-ray scattering (SAXS) reveals a homogeneous, conformal layer of SiO2 in the channels at a deposition rate of 1.7–1.8 Å per ALD cycle. Characterization by infrared and X-ray photoelectron spectroscopy (XPS) confirms the stoichiometric composition of the SiO2 films. Detailed XPS analysis reveals that the mechanism of SiO2 formation is based on subsurface crystal growth. By dissolving the polymer, the silica nanotubes are released from the ion-track membrane. The thickness of the tube wall is well controlled by the ALD process. Because the track-etched channels exhibited diameters in the range of nanometres and lengths in the range of micrometres, cylindrical tubes with an aspect ratio as large as 3000 have been produced.

scholarly journals Нанопроволоки из сплавов FeNi и FeCo: синтез, структура и мёссбауэровские измерения

2020 ◽  
Vol 62 (9) ◽  
pp. 1474
Author(s):  
И.М. Долуденко ◽  
Д.Л. Загорский ◽  
К.В. Фролов ◽  
И.В. Перунов ◽  
M.A. Чуев ◽  
...  
Keyword(s):  
Spontaneous Magnetization ◽  
Growth Conditions ◽  
Deposition Potential ◽  
Growth Potential ◽  
X Ray Diffraction ◽  
Matrix Synthesis ◽  
X Ray ◽  
Track Membranes ◽  
Feco Alloys ◽  
First Time

Nanowires (NWs) of FeNi and FeCo alloys were obtained by matrix synthesis based on galvanic filling of pores in track membranes. The change in the elemental composition of NWs when changing the composition of the electrolyte and when changing the deposition potential was studied. The effect of anomalous co-deposition of Fe is observed in the FeNi NWs: the iron content in the NWs is noticeably higher than that in the electrolyte. This difference increases when the initial concentration increases and when the growth potential decreases. An increase in the concentration of iron at the tops of the wires was also detected. For FeCo NWs, the composition corresponds to the composition of the electrolyte and did not change much when the potential changed. X-ray diffraction analysis allowed to determine the nature of changes in the spectra when the growth conditions change. The dependence of the X - ray spectra of FeNi on the growth potential is found- the intensity of the phase peaks changes. Mössbauer measurements revealed spontaneous magnetization for all samples of NW arrays along their axes. The dependence of the value of the ultrathin magnetic field Bh f on 57Fe nuclei on the composition of NWs (FexCo1−x and FexNi1−x) was obtained for the first time. It was found that the value of Bh f decreases with an increase in the speed of the electrodeposition process (or with an increase in the value of the deposition potential U).

scholarly journals Track membranes and their replicas as high-frequency phase-contrast objects in X-ray optics

2020 ◽  
Vol 12 (2) ◽  
pp. 173-190
Author(s):  
Alexander V. Mitrofanov ◽  
◽  
Alexey V. Popov ◽  
Dmitry V. Prokopovich ◽  
◽  
...  
Keyword(s):  
High Frequency ◽  
Phase Contrast ◽  
Ray Optics ◽  
X Ray ◽  
Track Membranes ◽  
Frequency Phase

A DEFT Way to Forecast Solar Flares

2021 ◽  
Vol 922 (2) ◽  
pp. 218
Author(s):  
Larisza D. Krista ◽  
Matthew Chih
Keyword(s):  
Space Weather ◽  
Solar Flares ◽  
Extreme Ultraviolet ◽  
Weather Forecast ◽  
Start Time ◽  
X Ray ◽  
Solar Observations ◽  
Solar Eruptions ◽  
Intensity Changes ◽  
Solar Ultraviolet

Abstract Solar flares have been linked to some of the most significant space weather hazards at Earth. These hazards, including radio blackouts and energetic particle events, can start just minutes after the flare onset. Therefore, it is of great importance to identify and predict flare events. In this paper we introduce the Detection and EUV Flare Tracking (DEFT) tool, which allows us to identify flare signatures and their precursors using high spatial and temporal resolution extreme-ultraviolet (EUV) solar observations. The unique advantage of DEFT is its ability to identify small but significant EUV intensity changes that may lead to solar eruptions. Furthermore, the tool can identify the location of the disturbances and distinguish events occurring at the same time in multiple locations. The algorithm analyzes high temporal cadence observations obtained from the Solar Ultraviolet Imager instrument aboard the GOES-R satellite. In a study of 61 flares of various magnitudes observed in 2017, the “main” EUV flare signatures (those closest in time to the X-ray start time) were identified on average 6 minutes early. The “precursor” EUV signatures (second-closest EUV signatures to the X-ray start time) appeared on average 14 minutes early. Our next goal is to develop an operational version of DEFT and to simulate and test its real-time use. A fully operational DEFT has the potential to significantly improve space weather forecast times.

The HEXITEC hard x-ray pixelated CdTe imager for fast solar observations

2016 ◽  
Author(s):  
Wayne H. Baumgartner ◽  
Steven D. Christe ◽  
Daniel F. Ryan ◽  
Andrew R. Inglis ◽  
Albert Y. Shih ◽  
...  
Keyword(s):  
X Ray ◽  
Solar Observations
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