FlowsandthePhotosphericMagneticFieldDynamicsat

Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,14 Feb 2006,*,Flows and the Photospheric Magnetic Field,Dynamics at Interior Corona Interface,Brian Welsch, George Fisher, Yan Li, &,the UCB/SSL MURI & CISM Teams,HMI Team Mtg., 2006,M1-H2: Mag. Activity,The Store and Release Paradigm (cf., earthquakes) motivates studying photospheric flows.,Slow,photospheric,motions (v 1 km/s) add magnetic energy to the coronal field, as,Poynting,flux.,-,E,x,B,-,(,v,x,B,) x,B,The “frozen-in flux” condition prevents relaxation,B,B,(P), so free energy is,stored,in the corona ,“latency.”,With enough free energy, the corona reaches an,unstable configuration,(?) and “,spontaneously,” relaxes toward,B,(P),.,Most CME models flux cancellation, breakout, tether cutting, kink,instability accord with this picture. (But even Chens 1996,“energy injection” paradigm also invokes,photospheric,flows!),Velocity inversions generate a 2D map,v,(x,1,x,2,)from some 2D image, f,1,(x,1,x,2,), to another, f,2,(x,1,x,2,).,The map depends upon:,the difference,f(x,1,x,2,) = f,2,(x,1,x,2,) f,1,(x,1,x,2,),assumption(s) relating,v,(x,1,x,2,) to,f/,t, e.g.:,continuity equation,f/,t +,t,(,v,t,f,) = 0, or,advection equation,f/,t + (,v,t,t,),f = 0, etc.,We apply,Fourier Local Correlation Tracking,(FLCT, Welsch,et,al.,2004), which assumes advection, to,magnetograms,.,(More on FLCT in M3:,Mag,. Data Products, Thurs.),Demoulin & Berger (2003) argued that LCT applied to magnetograms does not necessarily give plasma velocities,.,u,f,v,n,B,h,-,v,h,B,n,is the,flux transport velocity,u,f,is the,apparent,velocity (2 components),v,is the,actual,plasma velocity (3 comps),Motion of flux across photosphere,u,f, can be a combination of horizontal & vertical flows acting on non-vertical fields.,Ishii,et al,. (1998) explained complicated photospheric evolution in AR 5395 in terms of a complex, 3D flux system.,(a) schematic magnetogram; (b) sketch of 3D structure,Demoulin & Berger (2003) also argued that the flux transport velocity, with vector magnetograms, determines the fluxes of magnetic energy & helicity into the corona,.,E/,t = -,dS(,B,h, u,f,) B,n,dS,and,H/,t,-,dS(,A,h, u,f,) B,n,dS,where,B,n,= (,h,x,A,h,), n,We have implemented a,preliminary,automated “Magnetic Evolution Pipeline” (MEP).,cron,checks for new magnetograms with,wget,New MDI magnetograms are downloaded, deprojected, and tracked using,FLCT,.,The output stream includes deprojected m-grams,FLCT,flows (.,png,graphics files & ASCII data files), and tracking parameters.,Full documentation & all codes,(and bugs!),are on line.,Electric fields derived from pipelined velocities will be used as inputs for MHD models of the solar corona.,HMIs vector magnetogram coverage will improve accuracy of MHD boundary condition.,Hoped-for near term (1-2 years) improvements:,Extension of disk-side pipeline to,global pipeline,via estimation of far-side magnetic evolution.,Feature tracking, for estimation of,flux cancellation,rates.,Coronal models, e.g.,magnetic charge topology (MCT).,References,Dmoulin & Berger, 2003:,Magnetic Energy and Helicity Fluxes at the Photospheric Level, Dmoulin,P., and Berger,M.A.,Sol. Phys,.,v. 215, # 2, p. 203-215.,Ishii,et al, 1998:,Emergence of a Twisted Magnetic Flux Bundle as a Source of Strong Flare Activity,Ishii, T.T., Kurokawa, H., & Takeuchi, T.T., ApJ,v. 499, 898.,Schuck, 2005:,Local Correlation Tracking and the Magnetic Induction Equation,Schuck, P.,ApJ,v. 632, L53.,Welsch et al., 2004:,ILCT: Recovering Photospheric Velocities from Magnetograms by Combining the Induction Equation with Local Correlation Tracking, Welsch,B.T., Fisher,G.H., Abbett,W.P., and Regnier,S.,ApJ,v. 610, #2, p. 1148-1156.,