734 research outputs found
Measurements of the Sun's High Latitude Meridional Circulation
The meridional circulation at high latitudes is crucial to the build-up and
reversal of the Sun's polar magnetic fields. Here we characterize the
axisymmetric flows by applying a magnetic feature cross-correlation procedure
to high resolution magnetograms obtained by the Helioseismic and Magnetic
Imager (HMI) onboard the Solar Dynamics Observatory (SDO). We focus on
Carrington Rotations 2096-2107 (April 2010 to March 2011) - the overlap
interval between HMI and the Michelson Doppler Investigation (MDI). HMI
magnetograms averaged over 720 seconds are first mapped into heliographic
coordinates. Strips from these maps are then cross-correlated to determine the
distances in latitude and longitude that the magnetic element pattern has
moved, thus providing meridional flow and differential rotation velocities for
each rotation of the Sun. Flow velocities were averaged for the overlap
interval and compared to results obtained from MDI data. This comparison
indicates that these HMI images are rotated counter-clockwise by 0.075 degrees
with respect to the Sun's rotation axis. The profiles indicate that HMI data
can be used to reliably measure these axisymmetric flow velocities to at least
within 5 degrees of the poles. Unlike the noisier MDI measurements, no evidence
of a meridional flow counter-cell is seen in either hemisphere with the HMI
measurements: poleward flow continues all the way to the poles. Slight
North-South asymmetries are observed in the meridional flow. These asymmetries
should contribute to the observed asymmetries in the polar fields and the
timing of their reversals.Comment: 6 pages, 3 color figures, accepted for publication in The
Astrophysical Journal Lette
Doctrine of Bad Faith in the Law of Negotiable Instruments
This rule is now enacted in all but two of the states of the United States; the history of its development and of its application since it became undisputed is well illustrative of the process of the common law system, and this discussion is undertaken for the purpose of discovering the general principles which a trial court should have in mind when charging a jury in a case involving the application of this doctrine
Coronal Loop Analysis Using HINODE: EIS and XRT
The goal of this project is to analyze two loops, observed on 2007 December 9, todetermine their thermal and density properties. Data were obtained using the EUVImaging Spectrometer (EIS) and X-Ray Telescope (XRT) instruments onboard HINODE.Atomic physics data was obtained from the CHIANTI database. For the thermal analysisof Loop 1, observed intensities were used to create differential emission measure curvesto best fit the data. Density analysis was done using intensity ratios of density-sensitivelines. Results indicate that plasma in Loop 1 is multithermal. Loop 2 was found to exhibita structure that has yet to be reported in coronal loop literature. The structure appears tobe a very hot core with surrounding plasma that cools systematically as distance from thecore increases. Solar physics research at the University of Memphis is supported by NSFATM-0402729 and NASA NNG05GE68G
Photospheric Magnetic Flux Transport - Supergranules Rule
Observations of the transport of magnetic flux in the Sun's photosphere show that active region magnetic flux is carried far from its origin by a combination of flows. These flows have previously been identified and modeled as separate axisymmetric processes: differential rotation, meridional flow, and supergranule diffusion. Experiments with a surface convective flow model reveal that the true nature of this transport is advection by the non-axisymmetric cellular flows themselves - supergranules. Magnetic elements are transported to the boundaries of the cells and then follow the evolving boundaries. The convective flows in supergranules have peak velocities near 500 m/s. These flows completely overpower the superimposed 20 m/s meridional flow and 100 m/s differential rotation. The magnetic elements remain pinned at the supergranule boundaries. Experiments with and without the superimposed axisymmetric photospheric flows show that the axisymmetric transport of magnetic flux is controlled by the advection of the cellular pattern by underlying flows representative of deeper layers. The magnetic elements follow the differential rotation and meridional flow associated with the convection cells themselves -- supergranules rule
Wolf, Golden Eagle, and Coyote Problems in Montana
The average annual reported loss of sheep and lambs to predators in Montana from 1982 through 1986 was 46,000 animals worth 38,000
A Single Lineage In Early Pleistocene Homo : Size Variation Continuity In Early Pleistocene Homo Crania From East Africa And Georgia
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/97215/1/j.1558-5646.2012.01824.x.pd
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