Magnetic field measurements on the sun and implications for stellar magnetic field observations

AbstractThere should be a driving layer on the Sun, in which the interaction between magnetic field and plasma motion would provide enough magnetic energy and necessary topology for the explosion of solar activity in the corona.Although the exact location of the driving layer is not known, phenomenologically, the photosphere is acting, in many aspects, as the driving layer. Vector magnetic field measurements on the photosphere are greatly needed in clarifying the nature of the driving.Two elementary processes, flux emergence and cancellation, andone basic structure, magnetic interface between topology-independent magnetic loops, are key elements in the driving.

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Observing the Sun with the Atacama Large Millimeter/submillimeter Array – from continuum to magnetic fields

Proceedings of the International Astronomical Union ◽

10.1017/s1743921319009906 ◽

2019 ◽

Vol 15 (S354) ◽

pp. 24-37

Author(s):

Sven Wedemeyer ◽

Mikolaj Szydlarski ◽

Jaime de la Cruz Rodriguez ◽

Shahin Jafarzadeh

Keyword(s):

Magnetic Field ◽

Time Series ◽

Solar Magnetic Field ◽

Extended Period ◽

Field Measurements ◽

The Sun ◽

Post Processing ◽

Magnetic Field Measurements ◽

Scientific Results ◽

Temperature Maps

AbstractThe Atacama Large Millimeter/submillimeter Array offers regular observations of our Sun since 2016. After an extended period of further developing and optimizing the post-processing procedures, first scientific results are now produced. While the first observing cycles mostly provided mosaics and time series of continuum brightness temperature maps with a cadence of 1-2s, additional receiver bands and polarization capabilities will be offered in the future. Currently, polarization capabilities are offered for selected receiver bands but not yet for solar observing. An overview of the recent development, first scientific results and potential of solar magnetic field measurements with ALMA will be presented.

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Two Kinds of Activity in Late-type Stars

International Astronomical Union Colloquium ◽

10.1017/s0252921100080106 ◽

1991 ◽

Vol 130 ◽

pp. 440-442

Author(s):

M.M. Katsova

Keyword(s):

Magnetic Field ◽

Active Regions ◽

Field Measurements ◽

Spherically Symmetric ◽

The Sun ◽

Late Type ◽

X Ray ◽

Magnetic Field Measurements ◽

Local Magnetic Fields ◽

Uniform Manner

Several years ago we proposed a method for the analysis of X-ray observations of late-type stars. It allowed the determination in a uniform manner of coronal base electron densities for more than 40 late-type stars, in terms of a one-temperature consideration of homogeneous spherically symmetric coronae (Katsova et al., 1987). Fig. 1 shows the results as a function of spectral type. Comparison of our results with values for different kinds of solar regions shows that physical characteristics of F and G star coronae correspond to densities less than those in active regions on the Sun. Values for the active K-M0 stars are comparable with those of dense steady condensations found directly above large sunspots.On this basis, activity can be explained as an increase in that part of the stellar surface that is occupied by strong local magnetic fields. This is illustrated in the table where we compare magnetic field measurements by Saar and Linsky (1988) with our calculations.

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