Flare energy release and wave dynamics in nearby sunspot

Solar and Stellar Flares, Observations, simulations and synergies June 23 - 27, 2013, Prague, Czech Republic

Marian KarlickýAstronomical Institute, Fričova 278, 251 65

Ondřejov, Czech Republic

Robert Sych and Larisa Kashapova Institute of Solar-Terrestrial Physics, Irkutsk, Russia

Jaroslav DudíkCentre for Mathematical Sciences, University of

Cambridge, Cambridge CB3 OWA, UK

1. Dynamics of the 3-min waves in sunspot

a) Relation between sunspot waves and burst activity

b) Temporal dynamics and spatial structure of the 3-min waves

propagating upwards from the sunspot

c) Modes of the 3-min wave activity

2. The 07 June 2012 flare and wave processes in nearby sunspot

a) Flat shape SRX emission in decay phase of the flare

b) Wave dynamics above the sunspot in EUV and radio

c) Magnetic field connectivity of the sunspot and flare site

3. Conclusions

Contents

An example of the flaring activity on 2005 May 1: the correlation time profile of NoRH at 17 GHz.

Combined image of AR 10756 taken with NoRH at 17 GHz and in the optical band with TRACE on 2005 May 01 at 03:14:39 UT.

Relation between sunspot wave and burst activity

Sych, R.; Nakariakov, V. M.; Karlicky, M.; Anfinogentov, S. Astronomy and Astrophysics, 505, 2, 2009

Power Dynamics Power Dynamics Amplitude Dynamics Amplitude Dynamics

Original 3D Cube Data

Original 3D Cube Data

The temporal dynamics of the 3-min waves propagation on coronal level above sunspot

Sych, R. A. at all., Solar Physics, 266, 2, 2010

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04-May-2005 / TRACE 171A / 03:30-03:50 UT

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The spatial structure of 3-min radio and EUV sourcesduring the “quiet” and “disturbed” modes

Sych, R. A. at all., Solar Physics, 266, 2, 2010

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Temporal variation of narrowband EUV sources

Temporal variation of narrowband radio sources

The ‘burst’ mode of the 3-min wave activity

Sych, R.; Nakariakov, V. M.; Karlicky, M.; Anfinogentov, S.Astronomy and Astrophysics, 505, 2, 2009

EUV, X-ray and optical observation of the C1.5 solar flare in June 07, 2012

The Callisto BLEN radio spectrum observed in June 7, 2012.

Left: Temporal evolution of electron temperature (TE) and emission measure (EM) from the RHESSI spectra and EUV 131Å flux (AIA/SDO). Right: Temporal profiles of EUV emission (SDO/AIA), X-ray and microwave emission (NoRH, 17 GHz).

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6-12 KeV, counts

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The oscillations in footpoint of the burst loop before the flare

The narrowband EUV images (SDO/AIA, 171A) of power oscillation in sunspot. The period bandwidth is 8.3 mHz – 2.87 mHz. The images was obtained before the main pulse in 04:20 – 05:50 UT.

Left panel: The EUV image of the magnetic loop footpoint (sunspot) (SDO/AIA, 171A). Right panel: The narrowband image centered at 5.6 mHz frequency oscillations. Bottom panel: The global wavelet spectrum (GWS) of oscillations.

Sunspot waves as a trigger of flare activity

Top panel: The NoRH correlation profile in intensity (R+L) channel at 17 GHz. Middle panel: The power oscillation profile centered at 5.6 mHz frequency. The dotted line shows the trend of increasing 3-min oscillations before the radio burst. Bottom panel: The amplitude oscillations with 3-min period (left) and their power wavelet spectrum (right).

The movie of the “quiet” wave propagation with 5.6 mHz frequency at 171A (SDO/AIA). The dotted contours shows the sunspot in optics.

The time evolution of the microwave burst (NoRH, 17 GHz) coincided with June 07, 2002 flare. The snapshots for 05:53:20, 05:54:50, 05:58:50 and 06:10:20 UT is presented. The solid lines is intensity, dotted line is polarization. The background is EUV image at 171A.

The movie of the microwave burst at 17 GHz, overlapped on EUV image at 1700A (SDO/AIA). The solid lines is intensity, dotted line is polarization.

2D temporal dynamics of the radio sources on June 07, 2012

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Time-distance plot and 3-min waveguides during the June 07, 2012 flare at 171A and 94A

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Left panels: The time-distance plot of wave propagation at 171A 94A (SDO) and radio (NoRH). Right panel: The coronal waveguides (5.6 mHz) at 171A and magnetic waveguides from SDO/HMI magnetogram.

‘Burst’ stage‘Quiet’ stage

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EUV images of flare loops on June 07, 2012

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An evolution of the flare loops in 171 Å and 94 Å lines before and at the beginning of the June 7, 2012 at four times: (05:46:22 UT, 05:48:00 UT, 05:51:36 UT, and 05:54:21 UT). The arrows show the loop connecting the flaring loops and nearby sunspot (channel). The arrow 1 shows the hot flare loop under the channel, the arrow 2 shows twisted flaring loops.

The 171 and 94 Å loops (the arrows) formed at 06:10:36 UT, at location, where strongly twisted loops were found before the are.

A mechanisms for the modulation of the flaring emission by an external MHD wave:

The scenario proposed by Nakariakov et al. (2006): Energy of transverse (kink or sausage) oscillations of coronal loops can periodically leak toa magnetic neutral point or line situated nearby. The incoming fast magnetoacoustic waverefracts towards the neutral point, experiencing focussing and steepening. Thisperiodically generates very sharp spikes of electric current density in the vicinity of theneutral point. The instabilities can cause the onset of micro-turbulence and hence enhancethe plasma resistivity several orders of magnitude. This would lead to periodic triggeringof magnetic reconnection and manifestation of the loop oscillations as periodic variation ofthe flaring light curve.

The scenario proposed by Zaitsev & Stepanov (1989): The centrifugal force associated with the periodic longitudinal field-aligned wave motions can cause periodic transverse kink-like perturbations of the magnetic structures

A scenario of the June 7, 2012 flare based on the models of Zaitsev & Stepanov (1989) and Nakariakov et al. (2006) . A) Scenario at the beginning of the flare, and B) at the end of the flare.

Results

The 3-min narrowband PWF maps of the active regionextended V- and arrow-shaped sources situated over sunspot the arms extended towards the flare site; These arms the magnetic plasma channels link the sunspot and the flare site as waveguides. The energy of 3-min oscillations leaks out the sunspots in the form of field-aligned slow magnetoacoustic waves (e.g. De Moortel 2006). The power of the oscillation is variable max just before the burst as a flare precursor. The curvature of the magnetic field lines and the centrifugal force associated with the periodic longitudinal field-aligned wave motions cause periodic transverse kink-like perturbations of the magnetic structures (e.g. Zaitsev & Stepanov 1989) and reconnections. We suppose that the transverse waves, propagating along the magnetic loop, are a trigger of flare processes in twisted loops located below this magnetic loop. The wave energy, coming from sunspot to flare site the energy release can be kept up by additional triggering of reconnection or by suppressing of plasma thermal conductivity origination of flat-shape emission during the flare.

Thank you for your attention !