Erratum: “Tests and Comparisons of Velocity‐Inversion Techniques” (ApJ, 670, 1434 [2007])

Welsch, B. T.; Abbett, W. P.; DeRosa, Marc L.; Fisher, G. H.; Georgoulis, Manolis K.; Kusano, K.; Longcope, D. W.; Ravindra, B.; Schuck, P. W.

doi:10.1086/588021

Cited by 2 publications

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“…Under the idea of the multiple flux tube model (Welsch & Longcope 2003), there are three interpretations of helicity injection flux with writhe and twist: the single flux tube model, the multiple flux tube model, and the continuous field line model.…”

Section: Helicity Flux Interpretationsmentioning

confidence: 99%

“…One of our future subjects is to recalculate helicity injection fluxes in the events studied by Yamamoto and Sakurai (2009) with a single flux tube model. Welsch and Longcope (2003) analyzed helicity injection fluxes of magnetic patches in a quiet-Sun region. Longcope, Ravindra, and Barnes (2007a) developed an area partitioning method, and analyzed six active regions using equation (4).…”

Section: The Single Flux Tube Modelmentioning

confidence: 99%

“…At present, there are two major issues concerning the helicity flux calculation. One is how to obtain velocity fields on a boundary (e.g., Welsch et al 2007), and another is which of helicity injection equations is appropriate. The latter is the main issue in this paper.…”

Section: Introductionmentioning

confidence: 99%

“…Since Chae (2001), many authors have studied how to estimate velocity fields. For more precise descriptions, see Welsch et al (2007). On the other hand, helicity flux equations are another major issue.…”

Section: Introductionmentioning

confidence: 99%

“…On the other hand, helicity flux equations are another major issue. Welsch and Longcope (2003) studied helicity injection fluxes of magnetic patches in a quiet region, and showed a helicity injection equation divided into twist and writhe components. Longcope, Ravindra, and Barnes (2007a) studied helicity injection fluxes in active regions with a more generalized equation.…”

Section: Introductionmentioning

confidence: 99%

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Helicity Injection Fluxes of Twist and Writhe

Yamamoto¹

2011

Publications of the Astronomical Society of Japan

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We consider helicity flux equations proposed by previous authors and offer interpretations of these helicity injection equations with twist and writhe. At first, comparing Pariat's helicity flux equation (2005, A&A, 439, 1191) with Longcope's (2007, ApJ, 668, 571), we find that the Pariat's helicity injection equation shows helicity evolution of continuous magnetic field lines, which is an extreme case of the Longcope's multiple flux tube model. Next, we investigated Berger's helicity flux density (1984, J. Fluid Mech., 147, 133) and Pariat's on the positive and negative polarities, and confirmed that these equations produce different helicity fluxes on the positive and negative polarities. Under the idea of the multiple flux tube model, we propose two interpretations of helicity injection fluxes of twist and writhe; the single flux tube model and the continuous field line model. Recent results of helicity flux injections need to be reanalyzed.

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Section: Helicity Flux Interpretationsmentioning

confidence: 99%

Section: The Single Flux Tube Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Helicity Injection Fluxes of Twist and Writhe

Yamamoto¹

2011

Publications of the Astronomical Society of Japan

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Tracking Vector Magnetograms with the Magnetic Induction Equation

Schuck

2008

Astrophysical Journal

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232

193

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The differential affine velocity estimator (DAVE) developed in Schuck (2006) for estimating velocities from line-of-sight magnetograms is modified to directly incorporate horizontal magnetic fields to produce a differential affine velocity estimator for vector magnetograms (DAVE4VM). The DAVE4VM's performance is demonstrated on the synthetic data from the anelastic pseudospectral ANMHD simulations that were used in the recent comparison of velocity inversion techniques by Welsch (2007). The DAVE4VM predicts roughly 95% of the helicity rate and 75% of the power transmitted through the simulation slice. Inter-comparison between DAVE4VM and DAVE and further analysis of the DAVE method demonstrates that line-of-sight tracking methods capture the shearing motion of magnetic footpoints but are insensitive to flux emergence -- the velocities determined from line-of-sight methods are more consistent with horizontal plasma velocities than with flux transport velocities. These results suggest that previous studies that rely on velocities determined from line-of-sight methods such as the DAVE or local correlation tracking may substantially misrepresent the total helicity rates and power through the photosphere.Comment: 30 pages, 13 figure

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Erratum: “Tests and Comparisons of Velocity‐Inversion Techniques” (ApJ, 670, 1434 [2007])

Cited by 2 publications

References 0 publications

Helicity Injection Fluxes of Twist and Writhe

Helicity Injection Fluxes of Twist and Writhe

Tracking Vector Magnetograms with the Magnetic Induction Equation

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