Generation of a North/South Magnetic Field Component from Variations in the Photospheric Magnetic Field

We address the problem of calculating the transverse magnetic field in the solar wind outside of the hypothetical sphere called the source surface where the solar wind originates. This calculation must overcome a widely used fundamental assumption about the source surface -- the field is normally required to purely radial at the source surface. Our model rests on the fact that a change in the radial field strength at the source surface is a change in the field line density. Surrounding field lines must move laterally in order to accommodate this field line density change. As the outward wind velocity drags field lines past the source surface this lateral component of motion produces a tilt implying there is a transverse component to the field. An analytic method of calculating the lateral translation speed of the field lines is developed. We apply the technique to an interval of approximately two Carrington rotations at the beginning of 2011 using 2-h averages of data from the Helioseismic Magnetic Imager instrument on the Solar Dynamics Observatory spacecraft. We find that the value of the transverse magnetic field is dominated on a global scale by the effects of high latitude concentrations of field lines being buffetted by supergranular motions.Comment: 23 pages with 8 figures. Accepted by Solar Physics (LaTeX processing with aastex6.cls instead of solarphysics.cls due to compatibility issues

Solar Sources of Interplanetary Magnetic Clouds Leading to Helicity Prediction

This study identifies the solar origins of magnetic clouds that are observed at 1 AU and predicts the helical handedness of these clouds from the solar surface magnetic fields. We started with the magnetic clouds listed by the Magnetic Field Investigation (MFI) team supporting NASA's WIND spacecraft in what is known as the MFI table and worked backwards in time to identify solar events that produced these clouds. Our methods utilize magnetograms from the Helioseismic and Magnetic Imager (HMI) instrument on the Solar Dynamics Observatory (SDO) spacecraft so that we could only analyze MFI entries after the beginning of 2011. This start date and the end date of the MFI table gave us 37 cases to study. Of these we were able to associate only eight surface events with clouds detected by WIND at 1 AU. We developed a simple algorithm for predicting the cloud helicity which gave the correct handedness in all eight cases. The algorithm is based on the conceptual model that an ejected flux tube has two magnetic origination points at the positions of the strongest radial magnetic field regions of opposite polarity near the places where the ejected arches end at the solar surface. We were unable to find events for the remaining 29 cases: lack of a halo or partial halo CME in an appropriate time window, lack of magnetic and/or filament activity in the proper part of the solar disk, or the event was too far from disk center. The occurrence of a flare was not a requirement for making the identification but in fact flares, often weak, did occur for seven of the eight cases.Comment: 18 pages, 8 figures, 2 table

Long-Term Measurements of Sunspot Magnetic Tilt Angles

Tilt angles of close to 30,600 sunspots are determined using Mount Wilson daily averaged magnetograms taken from 1974 to 2012, and MDI/SoHO magnetograms taken from 1996 to 2010. Within a cycle, more than 90% of sunspots have a normal polarity alignment along the east-west direction following Hale's law. The median tilts increase with increasing latitude (Joy's law) at a rate of ~0.5 degree per degree of latitude. Tilt angles of spots appear largely invariant with respect to time at a given latitude, but they decrease by ~0.9degree per year on average, a trend which largely reflects Joy's law following the butterfly diagram. We find an asymmetry between the hemispheres in the mean tilt angles. On average, the tilts are greater in the southern than in the northern hemisphere for all latitude zones, and the differences increase with increasing latitude.Comment: 29 pages, 13 figures, to appear on ApJ, October 20, 2012 website: http://www2.ess.ucla.edu/~jingli/ApJ201210

Physical Origin of Differences among various Measures of Solar Meridional Circulation

We show that systematic differences between surface Doppler and magnetic element tracking measures of solar meridional flow can be explained by the effects of surface turbulent magnetic diffusion. Feature-tracking speeds are lower than plasma speeds in low and mid-latitudes, because magnetic diffusion opposes poleward plasma flow in low-latitudes whereas it adds to plasma flow at high latitudes. Flux transport dynamo models must input plasma flow; the model-outputs yield estimates of the surface magnetic feature tracking speed. We demonstrate that the differences between plasma speed and magnetic pattern speed in a flux-transport dynamo are consistent with the observed difference between these speeds.Comment: To appear in Ap

Solar Meridional Circulation from Doppler Shifts of the Fe I line at lambda 5250 Angstroms as Measured by the 150-foot Solar Tower Telescope at the Mt. Wilson Observatory

Doppler shifts of the Fe I spectral line at lambda5250 Angstroms from the full solar disk obtained over the period 1986 to 2009 are analyzed to determine the circulation velocity of the solar surface along meridional planes. Simultaneous measurements of the Zeeman splitting of this line are used to obtain measurements of the solar magnetic field that are used to select low field points and impose corrections for the magnetically induced Doppler shift. The data utilized is from a new reduction that preserves the full spatial resolution of the original observations so that the circulation flow can be followed to latitudes of 80 degrees N/S. The deduced meridional flow is shown to differ from the circulation velocities derived from magnetic pattern movements. A reversed circulation pattern is seen in polar regions for three successive solar minima. An surge in circulation velocity at low latitudes is seen during the rising phases of cycles 22 and 23.Comment: 34 pages, 12 figures, Accepted by Astrophysical Journa

Photospheric Velocities Measured at Mt. Wilson Show Zonal and Sectoral Flows Compose the Torsional Oscillations

The methods for reducing the observations from the 150-foot Tower Telescope on Mt.~Wilson are reviewed and a new method for determining the North/South (sectoral) and the East/West (zonal) velocity components is described and applied. Due to a calibration problem with the data prior to 1983, only observations between 1983 and 2013 are presented at this time. After subtraction of latitude dependent averages over the 30-year period of observation the residual deviations in the sectoral and zonal flow velocities are well synchronized and correspond to what is widely recognized as the Torsional Oscillations. Both flow components need to be included in any model that replicates the Torsional Oscillations.Comment: 15 pages, 5 figures, 1 table. Submitted to Solar Physics 7/12/202

Psychiatric ward design can reduce aggressive behavior

The article describes a conceptual model proposing that aggression in psychiatric facilities may be reduced by designing the physical environment with ten evidence-grounded stress-reducing features. The model was tested in a newer hospital in Sweden having wards with nine of the ten features. Data on two clinical markers of aggressive behavior, compulsory injections and physical restraints, were compared with data from an older facility (replaced by the newer hospital) that had only one stress-reducing feature. Another hospital with one feature, which did not change during the study period, served as a control. The proportion of patients requiring injections declined (p < 0.0027) in the new hospital compared to the old facility but did not change in the control hospital. Among patients who received injections, the average number of injections declined marginally in the new hospital compared to the old facility, but increased in the control hospital by 19%. The average number of physical restraints (among patients who received at least one) decreased 50% in the new hospital compared to the old. These findings suggest that designing better psychiatric buildings using reasoned theory and the best available evidence can reduce the major patient and staff safety threat posed by aggressive behavior

Tracing molybdenum attenuation in mining environments using molybdenum stable isotopes

Molybdenum contamination is a concern in mining regions worldwide. Better understanding of processes controlling Mo mobility in mine wastes is critical for assessing potential impacts and developing water-quality management strategies associated to this element. Here, we used Mo stable isotope (δ98/95Mo) analyses to investigate geochemical controls on Mo mobility within a tailings management facility (TMF) featuring oxic and anoxic environments. These isotopic analyses were integrated with X-ray absorption spectroscopy, X-ray diffraction, Raman spectroscopy, transmission electron microscopy, and aqueous chemical data. Dissolved Mo concentrations were inversely correlated with δ98/95Mo values such that enrichment of heavy Mo isotopes in solution reflected attenuation processes. Inner-sphere complexation of Mo(VI) with ferrihydrite was the primary driver of Mo removal and was accompanied by a circa 1 ‰ isotope fractionation. Limited Mo attenuation and isotope fractionation was observed in Fe(II)- and Mo-rich anoxic TMF seepage, while attenuation and isotope fractionation were greatest during discharge and oxidation of this seepage after discharge into a pond where Fe-(oxyhydr)oxide precipitation promoted Mo sorption. Overall, this study highlights the role of sorption onto Fe-(oxyhydr)oxides in attenuating Mo in oxic environments, a process which can be traced by Mo isotope analyses

Full-disk magnetograms obtained with a Na magneto-optical filter at the Mount Wilson Observatory

The first full-disk magnetograms to be obtained with the Na magneto-optical filter (MOF) which is located at the 60 foot solar tower of the Mount Wilson Observatory are presented. This MOF was employed as a longitudinal magnetograph on June 18, 19, and July 1, 1987. On those three days the MOF was combined with a large format (1024 x 1024 pixel) virtual phase change coupled device camera and a high-speed data acquisition system. The combined system was used to record both line-of-sight magnetograms and Dopplergrams which covered the entire visible solar hemisphere. The pixel size of these magnetograms and Dopplergrams was 2.3 arcseconds. On each of the three days a time series of nine pairs of magnetograms and Dopplergrams was obtained at the rate of one pair every two minutes. On the same three day longitudinal magnetograms have one arcsecond pixels were obtained with the vacuum telescope at Kitt Peak. The MOF and vacuum tower magnetograms were compared at both the JPL Multi-Mission Image Processing Laboratory and at USC and have found the two sets of images to be well correlated both in spatial distribution and strength of the measured magnetic field. The simultaneously-obtained MOF Dopplergrams to remove the crosstalk which was present between the Doppler and Zeeman shifts of the NaD lines from the magnetograms from all three days and will also describe recent improvements to the system which allowed the obtaining of full-disk magnetograms as rapidly as one every 25 seconds