scholarly journals Synoptic solar observations of the Solar Flare Telescope focusing on space weather

2020 ◽  
Vol 10 ◽  
pp. 41 ◽  
Author(s):  
Yoichiro Hanaoka ◽  
Takashi Sakurai ◽  
Ken’ichi Otsuji ◽  
Isao Suzuki ◽  
Satoshi Morita
Keyword(s):  
Magnetic Field ◽  
Solar Flare ◽  
Space Weather ◽  
Solar Observation ◽  
The Sun ◽  
Solar Observations ◽  
Solar Filaments ◽  
Field Information ◽  
Activity Cycles ◽  
Synoptic Observations

The solar group at the National Astronomical Observatory of Japan is conducting synoptic solar observation with the Solar Flare Telescope. While it is a part of a long-term solar monitoring, contributing to the study of solar dynamo governing solar activity cycles, it is also an attempt at contributing to space weather research. The observations include imaging with filters for Hα, Ca K, G-band, and continuum, and spectropolarimetry at the wavelength bands including the He I 1083.0 nm/Si I 1082.7 nm and the Fe I 1564.8 nm lines. Data for the brightness, Doppler signal, and magnetic field information of the photosphere and the chromosphere are obtained. In addition to monitoring dynamic phenomena like flares and filament eruptions, we can track the evolution of the magnetic fields that drive them on the basis of these data. Furthermore, the magnetic field in solar filaments, which develops into a part of the interplanetary magnetic cloud after their eruption and occasionally hits the Earth, can be inferred in its pre-eruption configuration. Such observations beyond mere classical monitoring of the Sun will hereafter become crucially important from the viewpoint of the prediction of space weather phenomena. The current synoptic observations with the Solar Flare Telescope is considered to be a pioneering one for future synoptic observations of the Sun with advanced instruments.

scholarly journals The frequency of stellar X-ray flares from a large-scale XMM-Newton sample

2015 ◽  
Vol 11 (S320) ◽  
pp. 134-137
Author(s):  
John P. Pye ◽  
Simon R. Rosen
Keyword(s):  
Solar System ◽  
Solar Flare ◽  
Space Weather ◽  
White Light ◽  
Large Scale ◽  
The Sun ◽  
X Ray ◽  
Cool Star ◽  
Exoplanetary Systems ◽  
Solar Type

AbstractWe present estimates of cool-star X-ray flare rates determined from the XMM-Tycho survey (Pyeet al. 2015, A&A, 581, A28), and compare them with previously published values for the Sun and for other stellar EUV and white-light samples. We demonstrate the importance of applying appropriate corrections, especially in regard to the total, effective size of the stellar sample. Our results are broadly consistent with rates reported in the literature for Kepler white-light flares from solar-type stars, and with extrapolations of solar flare rates, indicating the potential of stellar X-ray flare observations to address issues such as ‘space weather’ in exoplanetary systems and our own solar system.

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.

scholarly journals Sun-like Stars: magnetic fields, cycles and exoplanets

2015 ◽  
Vol 11 (A29A) ◽  
pp. 360-364
Author(s):  
Rim Fares
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Large Scale ◽  
Observational Constraints ◽  
The Sun ◽  
Field Generation ◽  
Large Scale Magnetic Field ◽  
Planetary Orbits ◽  
Activity Cycles ◽  
Magnetic Cycles

AbstractIn Sun-like stars, magnetic fields are generated in the outer convective layers. They shape the stellar environment, from the photosphere to planetary orbits. Studying the large-scale magnetic field of those stars enlightens our understanding of the field properties and gives us observational constraints for field generation dynamo models. It also sheds light on how “normal” the Sun is among Sun-like stars. In this contribution, I will review the field properties of Sun-like stars, focusing on solar twins and planet hosting stars. I will discuss the observed large-scale magnetic cycles, compare them to stellar activity cycles, and link that to what we know about the Sun. I will also discuss the effect of large-scale stellar fields on exoplanets, exoplanetary emissions (e.g. radio), and habitability.

scholarly journals Long-term Monitoring of Solar Activity by Amateur Astronomers

1988 ◽  
Vol 98 ◽  
pp. 177-180
Author(s):  
Klaus Reinsch
Keyword(s):  
Solar Activity ◽  
Editorial Staff ◽  
West Germany ◽  
Solar Observation ◽  
The Sun ◽  
Solar Observations ◽  
Long Term Monitoring ◽  
Term Monitoring ◽  
Solar Astronomy

Professional solar astronomy concentrates on the study of the atmosphere and interior of the Sun. Little attention is given to “classical” programmes, mainly statistical investigations of solar activity. Although the main properties of phenomena associated with the solar cycle seem to be understood there are still enough details to be explained, making it worthwhile monitoring different indicators of solar activity, even if no immediate results are to be expected. Such routine observations are ideal work of amateur astronomers.Members of West German local astronomical societies founded the journal Sonne in 1977 to combine their efforts on solar observations. The first issue was presented at a conference on amateur solar observation held in Berlin in April 1977. Sonne is compiled by an editorial staff of 23 amateurs from all over West Germany, and is distributed among nearly 500 readers in 20 countries. With the increasing number of foreign readers, the main articles in Sonne are provided with English abstracts.

scholarly journals The influence of solar wind turbulence on geomagnetic activity

2008 ◽  
Vol 15 (1) ◽  
pp. 53-59 ◽  
Author(s):  
D. Jankovičovà ◽  
Z. Vörös ◽  
J. Šimkanin
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Magnetic Reconnection ◽  
Interplanetary Magnetic Field ◽  
Space Weather ◽  
Coupled System ◽  
Statistical Moment ◽  
The Sun ◽  
H Index ◽  
Magnetic Turbulence

Abstract. The importance of space weather and its forecasting is growing as interest in studying geoeffective processes in the Sun – solar wind – magnetosphere – ionosphere coupled system is increasing. In this paper higher order statistical moments of interplanetary magnetic field and geomagnetic SYM-H index fluctuations are compared. The proper description of fluctuations in the solar wind can elucidate important aspects of the geoeffectivity of upstream turbulence and contribute to our understanding of space weather. Our results indicate that quasi-stationary intervals during both quiet and stormy periods have to be investigated in order to find correlations between upstream and geomagnetic conditions. We found that the fourth statistical moment (kurtosis), which was not considered in previous studies, appears to be a new geoeffective parameter. Intermittency of the magnetic turbulence in the solar wind can influence the efficiency of the solar wind – magnetosphere coupling through affecting magnetic reconnection at the Earth's magnetopause.

scholarly journals Absolute Measurements of Starspot Area and Temperature

1993 ◽  
Vol 137 ◽  
pp. 193-195
Author(s):  
James E. Neff ◽  
Douglas O’Neal ◽  
Steven H. Saar
Keyword(s):  
Magnetic Field ◽  
Magnetic Activity ◽  
Local Magnetic Field ◽  
The Sun ◽  
Late Type ◽  
Solar Observations ◽  
Absolute Measure ◽  
Standard Picture ◽  
Stellar Properties ◽  
Absolute Measurements

Photometric and spectroscopic variability of late-type stars frequently has been interpreted as evidence of magnetic activity. The standard picture of stellar activity – inherited from solar observations – includes cool, dark “spots” in the photosphere and hot, dense regions in the chromosphere and coronae. The immediate cause of each of these phenomena is a closed topology of the local magnetic field. Because stars appear as mere points of light, these localized phenomena have not been directly resolvable on stars other than the Sun. Most observed effects are produced by an asymmetric distribution of starspots. If the distribution is symmetric, it would escape detection by most current techniques of light-curve and line-profile modeling. Even more troubling, the stellar properties measured with these techniques describe only a difference between contrasting hemispheres, not an absolute measure.

scholarly journals Study of Interplanetary and Geomagnetic Response of Filament Associated CMEs

2018 ◽  
Vol 13 (S340) ◽  
pp. 83-84
Author(s):  
Kunjal Dave ◽  
Wageesh Mishra ◽  
Nandita Srivastava ◽  
R. M. Jadhav
Keyword(s):  
Magnetic Field ◽  
Geomagnetic Activity ◽  
Space Weather ◽  
Coronal Mass Ejections ◽  
The Sun ◽  
The Earth ◽  
Weather Events ◽  
Terrestrial Magnetic Field

AbstractIt has been established that Coronal Mass Ejections (CMEs) may have significant impact on terrestrial magnetic field and lead to space weather events. In the present study, we selected several CMEs which are associated with filament eruptions on the Sun. We attempt to identify the presence of filament material within ICME at 1AU. We discuss how different ICMEs associated with filaments lead to moderate or major geomagnetic activity on their arrival at the Earth. Our study also highlights the difficulties in identifying the filament material at 1AU within isolated and in interacting CMEs.

scholarly journals Design of a Full Stokes Polarimeter for Chromospheric Measurements with SOLIS/VSM

2014 ◽  
Vol 10 (S305) ◽  
pp. 186-190
Author(s):  
S. Gosain ◽  
J. W. Harvey
Keyword(s):  
Magnetic Field ◽  
Solar Rotation ◽  
Solar Observatory ◽  
The Sun ◽  
Polarization Modulator ◽  
National Solar Observatory ◽  
Synoptic Observations ◽  
Stokes Polarimetry ◽  
Near Future ◽  
Full Disk

AbstractThe synoptic observations of the magnetic field of the Sun have continued at the National Solar Observatory (NSO) since 1970s. The daily full-disk maps of the longitudinal magnetic field are regularly combined to form Carrington maps of the photospheric magnetic flux per solar rotation. These maps continue to be used by the international research community for a variety of studies related to solar magnetism as well as for space weather studies. The current NSO synoptic facility is the Synoptic Optical Long-term Investigation of the Sun (SOLIS), which regularly provides photospheric vector and chromospheric longitudinal full-disk magnetograms, among other data products. In the near future, an upgrade of SOLIS to produce chromospheric vector magnetograms is planned. We present the design of a new polarization modulator package for full Stokes polarimetry of the chromospheric Ca II 854.2 nm spectral line.

scholarly journals About long term modulation of cosmic rays in the 23-24 solar activity cycles

2021 ◽  
pp. 23-29
Author(s):  
Anatoly V. Belov ◽  
Raisa T. Gushchina ◽  
Victor Yanke
Keyword(s):  
Magnetic Field ◽  
Solar Activity ◽  
Cosmic Rays ◽  
Solar Magnetic Field ◽  
The Sun ◽  
Model Calculations ◽  
Activity Cycles ◽  
The Magnetic Field ◽  
Solar Activity Cycles

Recently, there has been a significant trend in magnetic fields on the Sun. The total magnetic field of the Sun from the end of the 22nd cycle of solar activity (SA) has more than halved and this decrease continues. Chan- ges in the magnetic field are the key to all the active phenomena occurring on the Sun and in the heliosphere and, accordingly, to processes in cosmic rays. In long-term CR variations in 23-24 cycles of SA the attenuation of the solar magnetic field is displayed and these variations turned out to be the smallest for the entire time of CR observations. Model calculations of CR modulation for 21-22 and 23-24 cycles of SA showed: with a slight difference in the regression characteristics obtained, the distribution of contributions to the generated CR modulation from the effects of various SA indices is strongly varies in the analyzed periods. Possible reasons for the features of the last two CA cycles are discussed.

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