X rays and solar wind composition in four comets observed with Chandra X-Ray Observatory

Interplanetary Scintillation (IPS) is a diffraction phenomenon in which coherent electro-magnetic radiation, from a distant radio source, passes through the solar wind, which is a turbulent refracting medium, and suffers scattering. This results in random temporal variations of the signal intensity (scintillation) at the Earth. IPS observations to monitor the interplanetary medium (IPM), to measure solar wind velocities in the directions of a number of compact extra-galactic radio sources and to estimate the angular diameters of their compact components have been carried out for many years at 103 MHz using the IPS facility (Alurkar et al. 1989) of the Physical Research Laboratory (PRL), Ahmedabad, India. Over a period of approximately 10 years of such observations, it has been seen that PSR 0950+08 has always remained well within the noise level. We observed a sudden enhancement in its flux (Deshpande et al. 1994) on 29 July, 1992. The ionospheric observations which are being carried out on a regular basis at PRL using an ionosonde also recorded a steep increase in the absorption index Fmin, which is an indicator of the excess ionization produced due to X-rays. During this period, the Sun was exceptionally quiet, thereby raising the question about the origin of the X-ray flux responsible for the observed steep rise in Fminduring the transit of PSR 0950+08.

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Implications of Solar Wind Composition for Cometary X‐Rays

The Astrophysical Journal ◽

10.1086/317176 ◽

2000 ◽

Vol 544 (1) ◽

pp. 558-566 ◽

Cited By ~ 115

Author(s):

N. A. Schwadron ◽

T. E. Cravens

Keyword(s):

Solar Wind ◽

X Rays ◽

Solar Wind Composition

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Charge-exchange soft x-ray emission of highly charged ions with inclusion of multiple-electron capture

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stab2537 ◽

2021 ◽

Author(s):

G Y Liang ◽

X L Zhu ◽

H G Wei ◽

D W Yuan ◽

J Y Zhong ◽

...

Keyword(s):

Solar Wind ◽

Electron Capture ◽

Charge Exchange ◽

Cross Sections ◽

Line Intensity ◽

X Rays ◽

Double Electron Capture ◽

X Ray ◽

Double Electron ◽

On Line

Abstract Charge-exchange has been recognized as a primary source of soft x-ray emission in many astrophysical outflow environments, including cometary and planetary exospheres impacted by solar wind. Some models have been setup by using different data collections of charge-exchange cross-sections. However, multiple electron transfer has not been included in these models. In this paper, we setup a charge exchange model with the inclusion of double-electron capture, and make a detailed investigation of this process on x-ray emissions of highly charged carbon, nitrogen, oxygen and neon ions by using available experimental cross-sections. We also study the effect of different n −selective cross-sections on soft x-ray emission by using available experimental n −distributions. This work reveals that double electron capture enhancement on line intensity is basically linearly proportional to the ratio of ion abundance in the solar wind. It is more obvious for soft x-rays from carbon ions (C4 +) in collision with CO2, and the enhancement on line intensity can be up to 53 per cent with typical ion abundances (ace observation) in solar wind. The synthetic spectra with parameters from the Ulysses mission for solar wind reveals velocity-dependence, target-dependence, as well as the non-negligible contribution from the double-electron capture.

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X-ray emission from the solar wind

Symposium - International Astronomical Union ◽

10.1017/s0074180900004617 ◽

1970 ◽

Vol 37 ◽

pp. 408-412

Author(s):

E. Boldt ◽

A. Klimas ◽

G. Sandri

Keyword(s):

Solar Wind ◽

Mean Free Path ◽

Ecliptic Plane ◽

Line Of Sight ◽

Astronomical Unit ◽

The Sun ◽

X Rays ◽

Electron Collisions ◽

X Ray ◽

Recent Developments

Recent developments have made it possible to detect cosmic X-rays with energies as low as several hundred eV. Several measurements of the diffuse X-radiation in this range have been reported (Baxter et al., 1969; Bowyer et al., 1968; Henry et al., 1968). In this note we investigate the possibility that these observers have detected X-radiation emitted by the solar wind. We conclude that they probably have not. However, we also find that bremsstrahlung may be detectable from a region of the sky near the sun. If this measurement is possible, it would represent an important method for determining some characteristics of the solar wind away from the ecliptic plane of the solar system. Even though the mean free path for electron collisions is large compared with the astronomical unit, the collision frequency, electron density, and energy released per encounter are sufficient to yield detectable soft X-radiation for lines of sight close to the sun. We have estimated the expected X-ray intensity in the vicinity of the earth on the basis of two models of the solar wind flow pattern; in the first, the flow is radial in all directions away from the sun, and in the second, the flow is confined to a disc of uniform thickness near the ecliptic. In both cases, we neglect temperature gradients for the electrons and compute the total flux received from interplanetary plasma along the line of sight. Most of the received intensity comes from the segment of the line of sight which is nearest the sun. The results are insensitive with respect to the position of the boundary of the solar cavity. Accordingly, we neglect the boundary and consider an infinitely large solar cavity.

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Imaging the Earth’s magnetic environment in soft X-rays with SMILE

10.5194/egusphere-egu2020-10877 ◽

2020 ◽

Author(s):

Graziella Branduardi-Raymont ◽

Steve Sembay ◽

Tianran Sun ◽

Hyunju Connor ◽

Andrey Samsonov

Keyword(s):

Solar Wind ◽

Joint Space ◽

Space Mission ◽

Standoff Distance ◽

X Rays ◽

X Ray ◽

The Earth ◽

X Ray Imaging ◽

Chinese Academy Of Sciences ◽

Academy Of Sciences

It is a relatively recent discovery that charge exchange soft X-ray emission is produced in the interaction of solar wind high charge ions with neutrals in the Earth&#8217;s exosphere; this has led to the realization that imaging this emission will provide us with a global and novel way to study solar-terrestrial interactions.In particular X-ray imaging will provide us with the means of establishing the location of the magnetopause and the morphology of the magnetospheric cusps. Variations of the magnetopause standoff distance indicate global magnetospheric compressions and expansions, both in response to solar wind variations and internal magnetospheric processes.Soft X-ray imaging is one of the main objectives of SMILE (Solar wind Magnetosphere Ionosphere Link Explorer), a joint space mission by ESA and the Chinese Academy of Sciences, which is under development and is due for launch in 2023. This presentation will introduce the scientific aims of SMILE, show simulations of the expected images to be returned by SMILE&#8217;s Soft X-ray Imager for different solar wind conditions, and will discuss some of the techniques that will be applied in order to extract the positions of the Earth&#8217;s magnetic boundaries, such as the magnetopause standoff distance.

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X-Ray Emission from the Solar System Bodies: Connection with Solar X-Rays and Solar Wind

10.1063/1.3395918 ◽

2010 ◽

Author(s):

Anil Bhardwaj ◽

M. Maksimovic ◽

K. Issautier ◽

N. Meyer-Vernet ◽

M. Moncuquet ◽

...

Keyword(s):

Solar Wind ◽

Solar System ◽

X Rays ◽

X Ray ◽

Solar System Bodies

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X-RAY EMISSION FROM PLANETS AND COMETS: RELATIONSHIP WITH SOLAR X-RAYS AND SOLAR WIND

Advances in Geosciences ◽

10.1142/9789812836229_0015 ◽

2009 ◽

pp. 229-244 ◽

Cited By ~ 2

Author(s):

ANIL BHARDWAJ ◽

RONALD F. ELSNER ◽

G. RANDALL GLADSTONE ◽

GRAZIELLA BRANDUARDI-RAYMONT ◽

KONRAD DENNERL ◽

...

Keyword(s):

Solar Wind ◽

X Rays ◽

X Ray

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White-Light Coronal Structures: Streamers and CMEs

International Astronomical Union Colloquium ◽

10.1017/s0252921100025045 ◽

1994 ◽

Vol 144 ◽

pp. 82

Author(s):

E. Hildner

Keyword(s):

Emission Line ◽

Electron Density ◽

White Light ◽

Coronal Mass Ejections ◽

X Rays ◽

Solar Cycles ◽

Temperature Function ◽

X Ray ◽

Eclipse Observations ◽

Coronal Structures

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.

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Chemical Species Identification in an SEM by Changes in Emitted X-Ray Energies

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052869 ◽

1974 ◽

Vol 32 ◽

pp. 570-571

Author(s):

R. H. Duff

Keyword(s):

Species Identification ◽

Valence Electron ◽

Chemical Species ◽

X Rays ◽

Chemical Bonds ◽

Small Shift ◽

X Ray ◽

Electron Transitions ◽

Peak Energy ◽

Chemical Combination

A material irradiated with electrons emits x-rays having energies characteristic of the elements present. Chemical combination between elements results in a small shift of the peak energies of these characteristic x-rays because chemical bonds between different elements have different energies. The energy differences of the characteristic x-rays resulting from valence electron transitions can be used to identify the chemical species present and to obtain information about the chemical bond itself. Although these peak-energy shifts have been well known for a number of years, their use for chemical-species identification in small volumes of material was not realized until the development of the electron microprobe.

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Influence of X-Ray Induced Fluorescence on Energy Dispersive X-Ray Analysis of Thin Foils

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100079164 ◽

1977 ◽

Vol 35 ◽

pp. 328-329

Author(s):

E. A. Kenik ◽

J. Bentley

Keyword(s):

Thin Foil ◽

Electron Excitation ◽

Simple Approach ◽

Foil Thickness ◽

X Rays ◽

X Ray ◽

Hole Spectrum ◽

Illumination System ◽

Thin Foils ◽

Intensity Ratios

Cliff and Lorimer (1) have proposed a simple approach to thin foil x-ray analy sis based on the ratio of x-ray peak intensities. However, there are several experimental pitfalls which must be recognized in obtaining the desired x-ray intensities. Undesirable x-ray induced fluorescence of the specimen can result from various mechanisms and leads to x-ray intensities not characteristic of electron excitation and further results in incorrect intensity ratios.In measuring the x-ray intensity ratio for NiAl as a function of foil thickness, Zaluzec and Fraser (2) found the ratio was not constant for thicknesses where absorption could be neglected. They demonstrated that this effect originated from x-ray induced fluorescence by blocking the beam with lead foil. The primary x-rays arise in the illumination system and result in varying intensity ratios and a finite x-ray spectrum even when the specimen is not intercepting the electron beam, an ‘in-hole’ spectrum. We have developed a second technique for detecting x-ray induced fluorescence based on the magnitude of the ‘in-hole’ spectrum with different filament emission currents and condenser apertures.

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