Heliospheric magnetic field strength and polarity from 1 to 81 AU during the ascending phase of solar cycle 23

2002 ◽  
Vol 107 (A11) ◽  
Author(s):  
L. F. Burlaga
Keyword(s):  
Magnetic Field ◽  
Solar Cycle ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Heliospheric Magnetic Field ◽  
Solar Cycle 23

scholarly journals Heliospheric magnetic field strength out to 66 AU: Voyager 1, 1978-1996

1998 ◽  
Vol 103 (A10) ◽  
pp. 23727-23732 ◽  
Author(s):  
L. F. Burlaga ◽  
N. F. Ness ◽  
Y.-M. Wang ◽  
N. R. Sheeley
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Heliospheric Magnetic Field

scholarly journals Pulsars and Bubble Dynamics

1997 ◽  
Vol 166 ◽  
pp. 223-226
Author(s):  
Ramen Kumar Parui
Keyword(s):  
Magnetic Field ◽  
Solar Cycle ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Bubble Dynamics ◽  
Recent Observation ◽  
Cosmic Ray ◽  
Activity Period ◽  
Cycle Period ◽  
Cosmic Ray Intensity

AbstractBased on recent observation of the dominance of the flare generated solar wind streams over the co-rotating streams and a significant lowering in the cosmic ray intensity in the abnormal year of the solar activity period, I have predicted the occurrence of discernible changes in magnetic field strength and the thickness of the shell of the local bubble during high sunspots years of the solar cycle period. In order to observe the variation, both in the magnetic field strength and in the thickness of the compressed shell, a proposal of continuous monitor of these two parameters through the observation of Faraday Rotation Measure has been proposed with an emphasize to the observations in the period of next abnormal year of the solar cycle in near future.

scholarly journals The magnetic nature of umbra–penumbra boundary in sunspots

2018 ◽  
Vol 611 ◽  
pp. L4 ◽  
Author(s):  
J. Jurčák ◽  
R. Rezaei ◽  
N. Bello González ◽  
R. Schlichenmaier ◽  
J. Vomlel
Keyword(s):  
Magnetic Field ◽  
Solar Cycle ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Field Component ◽  
Vertical Component ◽  
Vertical Magnetic Field ◽  
Intensity Threshold ◽  
The Magnetic Field ◽  
Magnetic Nature

Context. Sunspots are the longest-known manifestation of solar activity, and their magnetic nature has been known for more than a century. Despite this, the boundary between umbrae and penumbrae, the two fundamental sunspot regions, has hitherto been solely defined by an intensity threshold. Aim. Here, we aim at studying the magnetic nature of umbra–penumbra boundaries in sunspots of different sizes, morphologies, evolutionary stages, and phases of the solar cycle. Methods. We used a sample of 88 scans of the Hinode/SOT spectropolarimeter to infer the magnetic field properties in at the umbral boundaries. We defined these umbra–penumbra boundaries by an intensity threshold and performed a statistical analysis of the magnetic field properties on these boundaries. Results. We statistically prove that the umbra–penumbra boundary in stable sunspots is characterised by an invariant value of the vertical magnetic field component: the vertical component of the magnetic field strength does not depend on the umbra size, its morphology, and phase of the solar cycle. With the statistical Bayesian inference, we find that the strength of the vertical magnetic field component is, with a likelihood of 99%, in the range of 1849–1885 G with the most probable value of 1867 G. In contrast, the magnetic field strength and inclination averaged along individual boundaries are found to be dependent on the umbral size: the larger the umbra, the stronger and more horizontal the magnetic field at its boundary. Conclusions. The umbra and penumbra of sunspots are separated by a boundary that has hitherto been defined by an intensity threshold. We now unveil the empirical law of the magnetic nature of the umbra–penumbra boundary in stable sunspots: it is an invariant vertical component of the magnetic field.

scholarly journals Recovering the unsigned photospheric magnetic field from Ca II K observations

2019 ◽  
Vol 626 ◽  
pp. A114 ◽  
Author(s):  
Theodosios Chatzistergos ◽  
Ilaria Ermolli ◽  
Sami K. Solanki ◽  
Natalie A. Krivova ◽  
Fabrizio Giorgi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Cycle ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Power Law ◽  
Activity Level ◽  
Photospheric Magnetic Field ◽  
Stray Light ◽  
Magnetic Flux Density ◽  
Logarithmic Function

Context. A number of studies have aimed at defining the exact form of the relation between magnetic field strength and Ca II H and K core brightness. All previous studies have however been restricted to isolated regions on the solar disc or to a limited set of observations. Aims. We reassess the relationship between the photospheric magnetic field strength and the Ca II K intensity for a variety of surface features as a function of the position on the disc and the solar activity level. This relationship can be used to recover the unsigned photospheric magnetic field from images recorded in the core of Ca II K line. Methods. We have analysed 131 pairs of high-quality, full-disc, near-co-temporal observations from the Helioseismic and Magnetic Imager (SDO/HMI) and Precision Solar Photometric Telescope (Rome/PSPT) spanning half a solar cycle. To analytically describe the observationally determined relation, we considered three different functions: a power law with an offset, a logarithmic function, and a power-law function of the logarithm of the magnetic flux density. We used the obtained relations to reconstruct maps of the line-of-sight component of the unsigned magnetic field (unsigned magnetograms) from Ca II K observations, which were then compared to the original magnetograms. Results. We find that both power-law functions represent the data well, while the logarithmic function is good only for quiet periods. We see no significant variation over the solar cycle or over the disc in the derived fit parameters, independently of the function used. We find that errors in the independent variable, which are usually not accounted for, introduce attenuation bias. To address this, we binned the data with respect to the magnetic field strength and Ca II K contrast separately and derived the relation for the bisector of the two binned curves. The reconstructed unsigned magnetograms show good agreement with the original ones. Root mean square differences are less than 90 G. The results were unaffected by the stray-light correction of the SDO/HMI and Rome/PSPT data. Conclusions. Our results imply that accurately processed and calibrated Ca II K observations can be used to reconstruct unsigned magnetograms by using the relations derived in our study.

On the Configuration of the Magnetic Field of β CrB

1976 ◽  
Vol 32 ◽  
pp. 613-622
Author(s):  
I.A. Aslanov ◽  
Yu.S. Rustamov
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Radial Velocity ◽  
Magnetic Field Strength ◽  
Complex Shape ◽  
Rotation Period ◽  
Field Variation ◽  
Magnetic Field Variation ◽  
Secular Variations ◽  
The Magnetic Field

SummaryMeasurements of the radial velocities and magnetic field strength of β CrB were carried out. It is shown that there is a variability with the rotation period different for various elements. The curve of the magnetic field variation measured from lines of 5 different elements: FeI, CrI, CrII, TiII, ScII and CaI has a complex shape specific for each element. This may be due to the presence of magnetic spots on the stellar surface. A comparison with the radial velocity curves suggests the presence of a least 4 spots of Ti and Cr coinciding with magnetic spots. A change of the magnetic field with optical depth is shown. The curve of the Heffvariation with the rotation period is given. A possibility of secular variations of the magnetic field is shown.

2D analysis of magnetic field strength in GO SiFe steel sheets

1998 ◽  
Vol 08 (PR2) ◽  
pp. Pr2-579-Pr2-582 ◽  
Author(s):  
S. Tumanski ◽  
M. Stabrowski
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Steel Sheets

MAGNETIC FIELD, PRESSURE AND TEMPERATURE DEPENDENT OPTICAL PROPERTIES IN A GaAs 9.0 P 1.0 QUANTUM DOT

2014 ◽  
Vol 6 (2) ◽  
pp. 1178-1190
Author(s):  
A. JOHN PETER ◽  
Ada Vinolin
Keyword(s):  
Magnetic Field ◽  
Optical Properties ◽  
Quantum Dot ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Photon Energy ◽  
Nonlinear Optical ◽  
Binding Energies ◽  
Nonlinear Optical Properties ◽  
Optical Rectification

Simultaneous effects of magnetic field, pressure and temperature on the exciton binding energies are found in a 9.0 1.0 6.0 4.0 GaAs P / GaAs P quantum dot. Numerical calculations are carried out taking into consideration of spatial confinement effect. The cylindrical system is taken in the present problem with the strain effects. The electronic properties and the optical properties are found with the combined effects of magnetic field strength, hydrostatic pressure and temperature values. The exciton binding energies and the nonlinear optical properties are carried out taking into consideration of geometrical confinement and the external perturbations.Compact density approach is employed to obtain the nonlinear optical properties. The optical rectification coefficient is obtained with the photon energy in the presence of pressure, temperature and external magnetic field strength. Pressure and temperature dependence on nonlinear optical susceptibilities of generation of second and third order harmonics as a function of incident photon energy are brought out in the influence of magnetic field strength. The result shows that the electronic and nonlinear optical properties are significantly modified by the applications of external perturbations in a 9.0 1.0 6.0 4.0 GaAs P / GaAs P quantum dot.

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