Sakai, J. I., Nishi, K., and Sokolov, I. V. ApJ, 2002, 576, 1018 Heating of coronal loop footpoints by slingshot magnetic reconnection during two loop interactions driven by a moving solitary magnetic kink Sakai, J. I., Nishi, K., and Sokolov, I. V. ApJ, 2002, 576, 1018

Background-theories Possible coronal heating mechanism: MHD waves propagate and dissipate (e.g., Steiner et al. 1994, Ofman, et al. 1998, Sakurai, 1985 ) Current sheets heating at the topologic interface (e.g., Parker 1972, Glencross 1975, Rosner et al. 1978, Sturrock and Uchida 1981, Demoulin and Priest 1997)---- but it is hard to detect the existence of current in the corona at present

Background-observations TRACE EUV observations (Lenz et al. 1999; Aschwanden et al. 2000, 2001)  near-isothermal loop T structure, multithreads, heated near the footpoints for some EUV loops TRACE EUV observations (Schrijver 1999, Qiu et al. 1999)  existence of up- and downflows in active region loops

Sakai’s previous main results Collision of magnetic flux tubes  shock formation and upflows (2000a) Collision between the shock waves and the loops  surface Alfven waves (2000b) Nonlinear MHD wave propagation  upward torsional and compressional waves (2000c, 2001a) Surface Alfven waves and upward plasma  magnetic reconnection  Chromospheric loop heating model (2001b)

The present work To investigate reconnection between a vertical loop and a low-lying loop driven by the ‘moving solitary magnetic kink’ (MoSMak)  Coronal loop heating ?

Formation of a MoSMaK Head-on collision process of two dense plasma blobs in a twisted magnetic flux tube (the plasma blobs can be driven by the flux tube collisions near the photosphere) Iso-surface of |B|=0.32 A=2a/VA, a=20

Velocity structure of the MoSMaK Bx-By Vx-Vy (1) (2) (3) Iso-surface of |v|=0.2

Time evolution of the head-on collision process of two MoSMaKs Iso-surface of |B|=0.19 Horizontal loop Strong expanding toroidal flux

Time evolution of the iso-surface of |B|=0.19 Vertical loop Sling-shot reconnection appears

Time evolution of the iso-surface of |B|=0.31 with different view

Time evolution of By-Bz (x=100) Time evolution of Bx-Bz (y=100) Time evolution of By-Bz (x=100)

Time evolution of the iso-surface of |V|=0.15 Time evolution of Vy-Vz (x=100) Time evolution of the iso-surface of |V|=0.15

Velocity distribution on Z=200 at t=28

Vertical loop heating

conclusion A new local heating model of loop footpoints in the chromosphere is proposed Non-uniform heating by slingshot reconnection, driven by the MoSMaKs The loop interaction results in the formation of both helical up- and downflows