EVAPORATION FLOWS IN A BRIGHT KERNEL OF A X1.6 FLARE OBSERVED ON 2014 OCTOBER 22 BY IRIS, HINODE, AND RHESSI

Kyoung-Sun Lee1, Shinsuke Imada2, Kyoko Watanabe3, Yumi Bamba1,2

1Hinode team, ISAS/JAXA, 2 STELAB, Nagoya University, 3 Solar-C group, NAOJ

IRIS workshop 4

Solar flare – Models & observations 1. Introduction

•  Evaporation flows - From the spectroscopic observation, evaporation flows are observed by Doppler velocity measurements

•  Magnetic reconnection occurs •  Energetic particles are accelerated at the reconnection site

- Particles precipitates along the magnetic loop (radio emission) and hit the chromosphere footpoints (Hard X- ray emission, Hα emission and flare ribbon) - Heated chromospheric plasma evaporates into the corona (soft X-ray emission, post flare loop arcade)

Krucker et al. (2008)

X7.1 flare

Solar flare model

Spectroscopic observations of evaporation flows in flares • Previous studies for the

evaporation flows from spectroscopic observation

1. Introduction

Brosius (2013) – Hinode/EIS

Milligan et al. (2009) - Hinode/EIS

Tian et al. (2014) – IRIS

Fe XXIII

2. Observation X1.6 flare on 2014 October 22 (AR12192 ) - Simultaneous observation of IRIS, Hinode, SDO, and RHESSI HESSI Observing Summary Count Rates, Corrected

13:50 14:00 14:10 14:20 14:30 14:40Start Time (22-Oct-14 13:41:02)

10-1

100

101

102

103

104

105

Cor

rect

ed C

ount

Rat

e (s

-1 d

etec

tor-1

)

Det 1,3,93 - 6 keV6 - 12 keV12 - 25 keV25 - 50 keV50 - 100 keV100 - 300 keV300 - 800 keV800 - 7000 keV7000 - 20000 keV

Bright kernels in the flare 2. Observation

Background (blue): IRIS SJI 1330

Foreground (red): Hinode EIS Fe XII 195Å White box: IRIS raster for spectral window

Bright kernels in the flare 2. Observation

Background (blue): IRIS SJI 1330

Foreground (red): Hinode EIS Fe XII 195Å White box: IRIS raster for spectral window - Position 1: Before flare (13:34 UT / X:-254, Y:-307)

+

Bright kernels in the flare 2. Observation

Background (blue): IRIS SJI 1330

Foreground (red): Hinode EIS Fe XII 195Å White box: IRIS raster for spectral window - Position 1: Before flare (13:34 UT / X:-254, Y:-307) - Position 2: flare starts (14:06 UT / X:-248, Y:-320)

+

Bright kernels in the flare 2. Observation

Background (blue): IRIS SJI 1330

Foreground (red): Hinode EIS Fe XII 195Å White box: IRIS raster for spectral window - Position 1: Before flare (13:34 UT / X:-254, Y:-307) - Position 2: First peak of flare (14:06 UT / X:-248, Y:-320) - Position 3: Second peak of flare (14:20 UT / X:-254, Y:-318)

+

IRIS (single Gaussian) IRIS (double Gaussian) + EIS (single Gaussian) + EIS (double Gaussian)

Doppler velocity variation with formation temperatures – combination of IRIS and EIS

3. Results (1)

Blue shift

red shift

Explosive evaporation

Before flare (13:34 UT)

1st peak of the Flare (14:06 UT)

2nd peak of the Flare (14:24 UT)

a ~13:34 : brightening before the flare starts (cooler line shows blue shift) b ~14:06 : flare starts, impulsive phase (1st peak of the X-ray emission and white light flare occurring time) c ~14:30 : flare peak at the GOES X-ray curve (2nd peak of the X-ray emission and hotter emission intensity enhancement) d and e ~14:43, decay phase (sevral peaks of the intensity enhancement)

a b c d e

He II

O V

Fe X

Fe XII

Fe XIV

Fe XIV

Fe XV

Fe XVI

Fe XXIII

Fe XXIV

Temporal variation of the plasma properties – Intensity, Doppler velocity, and line width

3. Results (1)

•  IRIS (O I, Si IV, Fe XXI) – Position 1 – EIS Intensity a b c d e

Temporal variation of the plasma properties – Intensity, Doppler velocity, and line width

•  IRIS (O I, Si IV, Fe XXI) – Position 2 – EIS Intensity

3. Results (1)

He II

O V

Fe X

Fe XII

Fe XIV

Fe XIV

Fe XV

Fe XVI

Fe XXIII

Fe XXIV b c d e b c d e

Temporal variation of the plasma properties – Intensity, Doppler velocity, and line width

•  IRIS (O I, Si IV, Fe XXI) – Position 3 – EIS Intensity

3. Results (1)

He II

O V

Fe X

Fe XII

Fe XIV

Fe XIV

Fe XV

Fe XVI

Fe XXIII

Fe XXIV b c d e b c d e

Temporal variation of the HXR and SXR emission from the RHESSI

3. Results (3)

HXR (30-100 keV)

SXR (12-25 keV)

Red contour: SXR, Blue contour: HXR HXR peak – cooler line intensity SXR peak – hotter line intensity

Spectroscopic view of the evaporated flows in the bright kernels in the flare

•  Temporal evolution of the Doppler velocities at the bright kernel with different spectral lines •  Before the flare – Blue shift at the bright kernel at the most spectral lines •  During the impulsive phase (1st peak)

•  Explosive evaporation flows (EIS + IRIS) - cooler emission: red shift (~100km/s) - hotter emission: blue shift (~ 300-400 km/s) •  Intensity enhancement at the lower temperature (O I & Si IV)

-  impact of non-thermal particle -  O I emission doesn’t have significant Doppler velocity variation -  Si IV shows red shifted emission

•  Strong blue shift without intensity enhancement at the hotter emission (Fe XXI) •  Decay phase (2nd peak)

•  Intensity enhancement of the hotter emissions - evaporation flows and thermal emission

•  Several peak of the Doppler velocity and intensity - multiple reconnection? •  Continuous blue shift (hotter lines) and red shift (cooler lines)

4. Discussion (1)

Intensity variation of the bright kernel and a relation with HXR and SXR from RHESSI •  Intensity variation with time and different spectral lines

•  Cooler emission shows sharp intensity peak before the enhancement of the hotter emission - White light flare - O I intensity enhancement

•  Intensity enhancement of the spectral lines a little delay with increasing temperature

•  Temporal variation of the RHESSI HXR and SXR •  The peak of HXR emission (30-100 keV) is observed at the start of the

flare - White light flare occurring time – Chromospheric line intensity enhancement -> non-thermal particle

•  There are two peak of SXR emission (12-25 keV) are observed (1st: HXR peak, 2nd: ~18 min later)

- Around the timing of 2nd peak, we observed intensity enhancement of the hotter emission (coronal lines) -> thermal emission

4. Discussion (1)

•  We observed X1.6 flare on 2014 October 22 using IRIS+HINODE+RHESSI.

•  High temporal resolution and wide temperature coverage -  IRIS (8 sparse slit scan) : 15 s for an each slit, 2 min for a scan raster -  Temperature coverage form combined IRIS and EIS observation : log T ~ 4.5 – 7.2

•  From the Doppler velocity measurements, we observed the explosive evaporation at the flare bright kernel.

•  We investigated the temporal evolution of the intensity, Doppler velocity using the combined observation of the IRIS and EIS -  Impulsive phase: strong blue shift at the hotter lines (weak intensity enhancement)

and red shift at cooler lines (intensity enhancement).

•  HXR related with white light flare and chromospheric line intensity enhancement and SXR related with hotter spectral line intensity enhancement.

•  We plan to measure the density variation with time and different region to understand the evaporation process with the intensity variation.

5. Summary

THANK YOU