The Dependence of Ephemeral Region Emergence on Local Flux Imbalance

2008 ◽  
Vol 678 (1) ◽  
pp. 541-548 ◽  
Author(s):  
Hermance J. Hagenaar ◽  
Marc L. DeRosa ◽  
Carolus J. Schrijver
Keyword(s):  
Region Emergence

scholarly journals The relationship between flux emergence and subsurface toroidal magnetic flux

2019 ◽  
Vol 631 ◽  
pp. A27
Author(s):  
R. H. Cameron ◽  
J. Jiang
Keyword(s):  
Flux Density ◽  
Mean Field ◽  
Solar Observatory ◽  
Toroidal Field ◽  
Flux Emergence ◽  
Radial Field ◽  
Calibration Curves ◽  
Butterfly Wings ◽  
The Relationship ◽  
Region Emergence

Aims. The 1D mean-field equation describing the evolution of the subsurface toroidal field can be used with the observed surface radial field to model the subsurface toroidal flux density. Our aim is to test this model and determine the relationship between the observationally inferred surface toroidal field (as a proxy for flux emergence), and the modelled subsurface toroidal flux density. Methods. We used a combination of sunspot area observations and the surface toroidal field inferred from Wilcox Solar Observatory (WSO) line-of-sight magnetic field observations. We then compared them with the results of a 1D mean-field evolution equation for the subsurface toroidal field, driven by the observed radial field from the National Solar Observatory/Kitt Peak and SOLIS observations. Results. We derive calibration curves relating the subsurface toroidal flux density to the observed surface toroidal field strengths and sunspot areas. The calibration curves are for two regimes, one corresponding to ephemeral region emergence outside of the butterfly wings, the other to active region emergence in the butterfly wings. We discuss this in terms of the size and vertical velocity associated with the two types of flux emergence.

scholarly journals Magnetic Helicity Propagation from Inside the Sun

2005 ◽  
Vol 13 ◽  
pp. 97-100
Author(s):  
Dana Longcope
Keyword(s):  
Active Region ◽  
Flux Tube ◽  
Convection Zone ◽  
Active Regions ◽  
Magnetic Helicity ◽  
The Sun ◽  
Solar Convection Zone ◽  
Solar Convection ◽  
Region Emergence

AbstractModels of twisted flux tube evolution provide a picture of how magnetic helicity is propagated through the solar convection zone into the corona. According to the models, helicity tends toward an approximately uniform length-density along a tube, rather than concentrating at wider portions. Coronal fields lengthen rapidly during active region emergence, requiring additional helicity to propagate from the submerged flux tube. Recent observations of emerging active regions show an evolution consistent with this prediction, and no evidence of helicity concentrating in wider sections.

scholarly journals Solar active region emergence and flare productivity

2006 ◽  
Vol 2 (14) ◽  
pp. 614-614
Author(s):  
Silvia C. Dalla ◽  
Lyndsay Fletcher ◽  
Nicholas A. Walton
Keyword(s):  
Active Region ◽  
Solar Active Region ◽  
Virtual Observatory ◽  
The Sun ◽  
A Value ◽  
Significant Difference ◽  
Region Emergence ◽  
Two Populations ◽  
East West ◽  
Flare Productivity

AbstractWe use the workflow capabilities of the AstroGrid Virtual Observatory system (<http://www.astrogrid.org>) to analyse the relation between flare productivity and location of Active Region (AR) emergence on the Sun. Specifically, we investigate whether emergence of a new region near existing ones results in increased productivity of the new and/or pre-existing AR. To address this question, we build a series of workflows that perform queries to catalogues of regions and flares, and operations on the results of the queries. There is a strong East-West asymmetry in the location of emergence of new regions. We do not find a significant difference between the flaring rate of paired and isolated regions, when we choose a value of 12° as the cutoff between the two populations.

A theoretical model of values and behaviors that shape technology region emergence in developing contexts

2019 ◽  
Vol 55 (1) ◽  
pp. 179-191
Author(s):  
Brett Anitra Gilbert ◽  
Yuanyuan Li ◽  
Andres Velez-Calle ◽  
Marcus Crews
Keyword(s):  
Theoretical Model ◽  
And Behaviors ◽  
Region Emergence

ERRATUM: “THE DEPENDENCE OF EPHEMERAL REGION EMERGENCE ON LOCAL FLUX IMBALANCE” (2008, ApJ, 678, 541)

2010 ◽  
Vol 715 (1) ◽  
pp. 696-696 ◽  
Author(s):  
Hermance J. Hagenaar ◽  
Marc L. DeRosa ◽  
Carolus J. Schrijver
Keyword(s):  
Region Emergence

scholarly journals Molecular Epidemiology of CTX-M-Producing Escherichia coli in the Calgary Health Region: Emergence of CTX-M-15-Producing Isolates

2007 ◽  
Vol 51 (4) ◽  
pp. 1281-1286 ◽  
Author(s):  
Johann D. D. Pitout ◽  
Deirdre L. Church ◽  
Daniel B. Gregson ◽  
Barbara L. Chow ◽  
Melissa McCracken ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Molecular Epidemiology ◽  
Genetic Relatedness ◽  
Pulsed Field Gel Electrophoresis ◽  
Laboratory System ◽  
Molecular Surveillance ◽  
E Coli ◽  
Community Outbreaks ◽  
Region Emergence ◽  
M 14

ABSTRACT A study was designed to describe the molecular epidemiology of CTX-M-producing Escherichia coli over a 6-year period (2000 to 2005) in a large well-defined Canadian region with a centralized laboratory system. Molecular characterization was done by isoelectric focusing, PCR, and automated sequencing, while genetic relatedness was determined by pulsed-field gel electrophoresis with XbaI. Of the 552 viable extended-spectrum β-lactamase-producing E. coli isolates isolated, 354 (64%) were positive for bla CTX-M genes associated with ISEcp1; 211 produced CTX-M-14, 128 produced CTX-M-15, 5 produced CTX-M-2, 4 produced CTX-M-3, 4 produced CTX-M-24, and 2 produced CTX-M-27. CTX-M-positive isolates were significantly more resistant to the fluoroquinolones than CTX-M-negative isolates, while CTX-M-15 producers were more likely to be resistant to gentamicin and tobramycin. There was a predominance of CTX-M-14 during the first 4 years of the study period, with community outbreaks associated with cluster 14A during 2000, 2001, and 2003. A substantial increase in CTX-M-15 producers occurred during the last 18 months and was due to clusters 15A and 15AR (where AR indicates related to A) in the hospital and nursing home sectors. Our results demonstrate that the persistence and dissemination of CTX-M genes among E. coli populations in larger geographic health care regions is dynamic, with the continuous emergence of clonally related CTX-M-15. This study illustrates the importance of molecular surveillance in tracking CTX-M-producing E. coli strains in the community and investigating their influx into hospitals.

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