scholarly journals On the Possibility of Radio Observations of Current Sheets on the Sun

1980 ◽  
Vol 86 ◽  
pp. 445-455
Author(s):  
S.I. Syrovatskii ◽  
V.D. Kuznetsov
Keyword(s):  
Electron Density ◽  
Optical Depth ◽  
Solar Atmosphere ◽  
Critical Frequency ◽  
Angular Resolution ◽  
The Sun ◽  
Radio Observations ◽  
Current Sheets ◽  
Large Intensity ◽  
Temperature Electron

Possibility of a discovery of current sheets in the radioband by using their screening and reflective properties as also their own emission is discussed. It is shown, that the thermal bremsstrahlung of the sheet may be of a sufficiently large intensity on the maximal critical frequency for the plasma in the sheet. In dependence from electron density No and temperature Ts the thickness of the sheet from tens centimetres to hundreds metres is sufficient to provide optical depth Spectral observations with sufficient angular resolution may give such characteristics of the sheet as its temperature, electron density, thickness and height in the solar atmosphere.

Diagnostics of current sheets on the sun using radio observations

1981 ◽  
Vol 24 (4) ◽  
pp. 271-275
Author(s):  
V. D. Kuznetsov ◽  
S. I. Syrovatskii
Keyword(s):  
The Sun ◽  
Radio Observations ◽  
Current Sheets

On the Possibility of Radio Observations of Current Sheets on the Sun

1980 ◽  
pp. 445-455 ◽  
Author(s):  
S. I. Syrovatskii ◽  
V. D. Kuznetsov ◽  
P. N. Lebedev
Keyword(s):  
The Sun ◽  
Radio Observations ◽  
Current Sheets

Radioastronomy through an Artificial Ionospheric Window—Spacelab 2 Observations

1986 ◽  
Vol 6 (3) ◽  
pp. 331-333
Author(s):  
G. R. A. Ellis ◽  
A. Klekociuk ◽  
G. T. Goldstone ◽  
Michael Medillo
Keyword(s):  
Radio Emission ◽  
Electron Density ◽  
Angular Resolution ◽  
Low Frequency ◽  
Radio Observations ◽  
Ionospheric Electron Density ◽  
Plasma Depletion ◽  
Galactic Background ◽  
Made In

Abstract Observations of the galactic background radio emission at a number of frequencies between 2.7 MHz and 1.07 MHz were made in association with the plasma depletion experiments of Spacelab-2 to test the concept of making low frequency radio observations through an artificial ionospheric window. Following the Shuttle OMS burn at a time when foF2 was 1.99 MHz, a decrease in the maximum ionospheric electron density of approximately 30% occurred. The first observations of the radio emission at high galactic latitudes with good angular resolution (25 degrees) were obtained during this event.

scholarly journals Physical Conditions in the Compact Planetary Nebula Sw St 1

1983 ◽  
Vol 103 ◽  
pp. 520-520
Author(s):  
M. Cohen ◽  
D.R. Flower ◽  
A. Goharji
Keyword(s):  
Electron Density ◽  
Planetary Nebula ◽  
Emission Measure ◽  
Emission Feature ◽  
Radio Observations ◽  
Physical Conditions ◽  
Infra Red ◽  
High Emission

Sw St 1 is a compact and possibly young planetary nebula which has been recently observed at infra red (Aitken et al., 1979) and radio (Kwok et al., 1981) wavelengths. In the 8-13 μm region, a silicate emission feature is observed, suggesting that the nebular envelope is oxygen rich. The high emission measure determined from the radio observations implies a large value for the electron density.

Correlations of solar-flare electron events with radio and X-ray emission from the sun

1968 ◽  
Vol 46 (10) ◽  
pp. S757-S760 ◽  
Author(s):  
R. P. Lin
Keyword(s):  
Solar Flare ◽  
Solar Radio ◽  
Interplanetary Space ◽  
The Sun ◽  
Radio Bursts ◽  
Radio Observations ◽  
X Ray ◽  
Type Iii ◽  
Electron Event ◽  
Burst Emission

The > 40-keV solar-flare electrons observed by the IMP III and Mariner IV satellites are shown to be closely correlated with solar radio and X-ray burst emission. In particular, intense type III radio bursts are observed to accompany solar electron-event flares. The energies of the electrons, the total number of electrons, and the size of the electron source at the sun can be inferred from radio observations. The characteristics of the electrons observed in interplanetary space are consistent with these radio observations. Therefore these electrons are identified as the exciting agents of the type III emission. It has been noted that the radio and X-ray bursts are part of the flash phase of flares. The observations indicate that a striking feature of the flash phase is the production of electrons of 10–100 keV energies.

scholarly journals 10. Radio observations of interstellar neutral hydrogen clouds

1957 ◽  
Vol 4 ◽  
pp. 66-66
Author(s):  
R. S. Lawrence
Keyword(s):  
Angular Resolution ◽  
Neutral Hydrogen ◽  
Optical Component ◽  
Absorption Lines ◽  
Radio Observations ◽  
Interstellar Absorption ◽  
Peak Intensity

The detailed relationship between optical interstellar absorption lines and 21-cm. observations is investigated in this paper.Dr Guido Münch, of the Mount Wilson and Palomar Observatories, provided the list of six intermediate-latitude stars shown in Table 1. The spectra of these stars all show complex absorption lines due to interstellar Ca 11. The 21-cm. line is measurable in four of the six regions, although the peak intensity is low in each case. It is noteworthy that for the first two stars on the list the radio velocity agrees closely with the velocity of an intense optical component. In view of the great difference in angular resolution, the failure to find correspondence in every case is not surprising.

scholarly journals The Tor Vergata Synoptic Solar Telescope (TSST): A robotic, compact facility for solar full disk imaging

2020 ◽  
Vol 10 ◽  
pp. 58
Author(s):  
Luca Giovannelli ◽  
Francesco Berrilli ◽  
Daniele Calchetti ◽  
Dario Del Moro ◽  
Giorgio Viavattene ◽  
...  
Keyword(s):  
Solar Atmosphere ◽  
Space Weather ◽  
Coronal Mass Ejections ◽  
Low Cost ◽  
Optical Filter ◽  
Solar Telescope ◽  
The Sun ◽  
Weather Events ◽  
Line Observation ◽  
Full Disk

By the continuous multi-line observation of the solar atmosphere, it is possible to infer the magnetic and dynamical status of the Sun. This activity is essential to identify the possible precursors of space weather events, such as flare or coronal mass ejections. We describe the design and assembly of TSST (Tor Vergata Synoptic Solar Telescope), a robotic synoptic telescope currently composed of two main full-disk instruments, a Hα telescope and a Potassium (KI D1) magneto-optical filter (MOF)-based telescope operating at 769.9 nm. TSST is designed to be later upgraded with a second MOF channel. This paper describes the TSST concepts and presents the first light observation carried out in February 2020. We show that TSST is a low-cost robotic facility able to achieve the necessary data for the study of precursors of space weather events (using the magnetic and velocity maps by the MOF telescope) and fast flare detection (by the Hα telescope) to support Space Weather investigation and services.

Numerical analysis of the neutral beam attenuation rate on the HT-7 and EAST tokamaks

2008 ◽  
Vol 74 (1) ◽  
pp. 9-19 ◽  
Author(s):  
GUOPING ZHANG ◽  
LIQUN HU ◽  
XIANMEI ZHANG ◽  
JUAN HUANG ◽  
JIN LIU ◽  
...  
Keyword(s):  
Electron Density ◽  
Neutral Beam ◽  
Beam Power ◽  
Impurity Effect ◽  
Atomic Processes ◽  
Ion Temperature ◽  
Plasma Parameters ◽  
Beam Attenuation ◽  
Attenuation Rate ◽  
Temperature Electron

AbstractA diagnostic neutral beam (DNB) is applied to measure the plasma ion temperature and rotation speed in the HT-7 tokamak. Also, a heating neutral beam (HNB) is suggested as an effective method of heating a plasma for the EAST tokamak. As a necessary step to evaluate the required beam power in both applications, the attenuation of the injected neutral beam has been numerically calculated and analyzed considering the effect of various plasma parameters, such as electron temperature, electron density, impurity concentration, and so on. Three basic atomic processes are considered here. It is shown that at the same electron density neutral beam particles can penetrate deeper at higher injection energies and a DNB with the same full energy can attenuate faster at higher electron densities. The impurity effect on the attenuation of a DNB is discussed, and the attenuation of a HNB on the EAST tokamak is also considered.

scholarly journals [no title]

1977 ◽  
Vol 4 (2) ◽  
pp. 375-387
Author(s):  
D. J. Mullan
Keyword(s):  
Solar Atmosphere ◽  
Solar Radius ◽  
The Sun ◽  
Length Scales ◽  
Amount Of Information ◽  
Physical Mechanisms

Heterogeneities in the solar atmosphere exist on many different length scales ranging from values as large as the solar radius (~106 km) down to features which are identifiable only by interferometry (~102 km). Rather than simply cataloguing the observed parameters of each and every known type of heterogeneity, I would like to concentrate on a few types of heterogeneities, with a view to identifying the information which is currently available concerning the physical mechanisms responsible for creating the in homogeneities. It is only if we can first identify the physics of each type of heterogeneity that we can hope to take even the first step towards predicting how each particular heterogeneity should scale to other stars. Since the present session is a joint discussion among mainly stellar astronomers, I feel that this approach is probably the most favorable method to present some of the large amount of information now available on solar features. Of course we expect that our solar information will be of most use to stellar astronomers in interpreting observations of stars which have similar spectral types to the sun. Nevertheless, we hope that nature will be kind enough to allow us to scale at least some of our information over a non-negligible area in the H.R. diagram.

The Sun

2015 ◽  
Author(s):  
Joanna D. Haigh ◽  
Peter Cargill
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Solar Atmosphere ◽  
Space Weather ◽  
Extreme Ultraviolet ◽  
The Sun ◽  
Base Level ◽  
Earth’S Climate ◽  
The Magnetic Field ◽  
Terrestrial Magnetic Field

This chapter discusses how there are four general factors that contribute to the Sun's potential role in variations in the Earth's climate. First, the fusion processes in the solar core determine the solar luminosity and hence the base level of radiation impinging on the Earth. Second, the presence of the solar magnetic field leads to radiation at ultraviolet (UV), extreme ultraviolet (EUV), and X-ray wavelengths which can affect certain layers of the atmosphere. Third, the variability of the magnetic field over a 22-year cycle leads to significant changes in the radiative output at some wavelengths. Finally, the interplanetary manifestation of the outer solar atmosphere (the solar wind) interacts with the terrestrial magnetic field, leading to effects commonly called space weather.

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