PTA, September 21, 2005 Solar flares in the new millennium H.S. Hudson Space Sciences Lab, UC Berkeley

PTA, September 21, 2005 Solar flares since 1991 H.S. Hudson Space Sciences Lab, UC Berkeley

PTA, September 21, 2005 Solar physics is no longer the only branch of astrophysics in which movies can be considered to be data…

PTA, September 21, 2005 Schema (inspired by R. Genzel) Object: Galactic Center Astronomer’s view: Black hole! Astrophysicist’s view: We can learn about relativity, gravity, etc in a new environment! Object: Solar Flare Astronomer’s view: Magnetic reconnection! Astrophysicist’s view: We can learn about plasma behavior in a new environment!

PTA, September 21, 2005 What is the solar corona? Low-beta plasma in a concentric cavity Slowly-varying lower boundary condition imposing vertical currents Body currents (and current sheets) in an isopotential volume Massive solar wind forming a lumpy upper boundary Flaring (flares and CMEs)

PTA, September 21, 2005 G. A. Gary, Solar Phys. 203, 71 (2001) (v A ~ 200  -1/2 km/s) CH Distribution of coronal plasma 

PTA, September 21, 2005 Yohkoh, RHESSI, TRACE and ground-based data: Recent wonders and marvels

PTA, September 21, 2005 Movie of dimming (Aug 28, 1992) Coronal Dimming

PTA, September 21, 2005 TRACE 1600A TRACE 171A Shrinkage, dimming, destruction, oscillation Helix, ribbons (separatrices?)

PTA, September 21, 2005 RHESSI  -ray imaging

PTA, September 21, x10 20 Mx -1.02x10 20 Mx +1.91x10 20 Mx +0.19x10 20 Mx +0.63x10 20 Mx -0.27x10 20 Mx I II III IV V VI Courtesy Y.H. Yang; cf H.M. Wang et al., ApJ 576, 497 (2002)

PTA, September 21, 2005 Flare/CME energetics

PTA, September 21, 2005 Kopp et al., 2004

PTA, September 21, 2005 Dennis et al., 2005

PTA, September 21, 2005 If these SEPs are accelerated by CME-driven shocks, they use a significant fraction of the shock kinetic energy (~3% to 20%) (Mewaldt et al., 2005; see also Emslie et al. 2005).

PTA, September 21, 2005 Flare development: magnetic restructuring and energy transport

PTA, September 21, 2005 Evidence for a large-scale coronal current sheet? Sui & Holman, 2004 Anzer & Pneuman, 1982

PTA, September 21, 2005 MDI magnetic artifacts

PTA, September 21, 2005 “Opacity minimum” flare IR observations (Xu et al., 2004)

PTA, September 21, 2005 Deposited Energy vs Footpoint Separation Mar 18, 2003 From Magnetogram: B fp  500 G Assume: B corona  B fp /5 A r = L h ·L v  360 arcsec 2 Perpendicular motion From HXR image: L h  5-10 arcsec  L v  arcsec (lower limit !!)

PTA, September 21, 2005 Shrinking magnetic field? Veronig et al., 2005; now have ~5 RHESSI events

PTA, September 21, 2005 TRACE observations of white light and UV emissions, flare of 2004 July 22 n.b. TRACE “white-light” response includes the UV, hence most of the flare luminosity “White light”Difference (reversed) UV 1700A

PTA, September 21, 2005 Coronal magnetic field Quantitative before/after magnetic models Aly conjecture Use of images (“data assimilation”) Problems - focusing the energy, accelerating particles, launching shock What is the eigenmode structure of an active region?

PTA, September 21, 2005 “Isomagnetobars” Before After

PTA, September 21, 2005 End

PTA, September 21, 2005 Microflares and jets

PTA, September 21, 2005 One month of RHESSI microflare observations Map of ~2000 flare locations of tiny flares seen by RHESSI (microflares) RHESSI microflares take place in active regions Rauscher et al. 2004

PTA, September 21, 2005 Imaging the bremsstrahlung from type III burst electrons?

PTA, September 21, 2005 X17 flare of 2005 Sept. 7 17:17 UT (courtesy S. Krucker) cf. Qiu et al. 2004