Microflare Activity driven by Forced Magnetic Reconnection

Abstract

High cadence, multiwavelength, optical observations of a solar active region are presented, obtained with the Swedish Solar Telescope. Two magnetic bright points are seen to separate in opposite directions at a constant velocity of 2.8km/s. After a separation distance of approximately 4400km is reached, multiple Ellerman bombs are observed in both H-alpha and Ca-K images. As a result of the Ellerman bombs, periodic velocity perturbations in the vicinity of the magnetic neutral line, derived from simultaneous MDI data, are generated with amplitude +/- 6km/s and wavelength 1000km. The velocity oscillations are followed by an impulsive brightening visible in H-alpha and Ca-K, with a peak intensity enhancement of 63%. We interpret these velocity perturbations as the magnetic field deformation necessary to trigger forced reconnection. A time delay of approximately 3min between the H-alpha wing and Ca-K observations indicate that the observed magnetic reconnection occurs at a height of 200km above the solar surface. These observations are consistent with theoretical predictions and provide the first observational evidence of microflare activity driven by forced magnetic reconnection.

2 Figures, accepted as an ApJ Letter

References in corpus (5)

• RHESSI Microflare Statistics II. X-ray Imaging, Spectroscopy & Energy Distributions
• Do all Flares have White Light Emission?
• Explosive events associated with a surge
• Automated Detection and Tracking of Solar Magnetic Bright Points
• Twisting Flux Tubes as a cause of Micro-Flaring Activity

Cited by in corpus (19)

• Ellerman bombs: fallacies, fads, usage
• Ellerman Bombs - Evidence for Magnetic Reconnection in the Lower Solar Atmosphere
• Statistical Analysis of Small Ellerman Bomb Events
• A study of Magnetic Bright Points in the Na I D1 line
• Numerical Simulation of Solar Microflares in a Canopy-Type Magnetic Configuration
• On the observations of rapid forced reconnection in the solar corona
• Granular-Scale Elementary Flux Emergence Episodes in a Solar Active Region
• Onset of turbulent fast magnetic reconnection observed in the solar atmosphere
• Statistical Signatures of Nanoflare Activity. I. Monte Carlo Simulations and Parameter-space Exploration
• The Multiple Continuum Components in the White Light Flare of 16 January 2009 on the dM4.5e Star YZ CMi
• Nanoflare Activity in the Solar Chromosphere
• Ultra-high-resolution Observations of MHD Waves in Photospheric Magnetic Structures
• Chromospheric Velocities of a C-class Flare
• Chromospheric Inversions of a Micro-flaring Region
• Three-dimensional Magnetic and Thermodynamic Structures of Solar Microflares
• Heating of solar chromosphere by electromagnetic wave absorption in a plasma slab model
• Moving Plasma Structures and Possible Driving Mechanisms of Solar Microflares Observed with High-Resolution Coronal Imaging
• Slow and sausage loop mode excitation due to local and global spontaneous perturbations
• The prominence driven forced reconnection in the solar corona and associated plasma dynamics