Physics of Chromospheric Evaporation in Solar Flares

K. Shibata

２００３ . 　 Apr 　２８　　　 Solar Seminar

Best 10 of Most cited papers based on Hida-DST observations 6th-10th

(ADS ： 2003 Apr 27)

• 6. Brueckner, G. E., et al. (1988) ApJ, 335, 986 ------------------- 18 回

• 7. Kurokawa, H., Hanaoka, H., et al. (1987) Solar Phys., 108, 251 --------- 17

• 8. Tsubaki, T., et al. (1988) PASJ, 40, 121 ----------------- 17

• 9. Culhane, J. L. et al. (1994) Solar Phys., 153, 307 -------- 16

• 10. Kitai, R. (1986) Solar Phys., 104, 287 -------- 16

Best 10 of Most cited papers based on Hida-DST observations 1st – 5th

• 1.

• ２ . Ichimoto, K. (1987) Solar Phys. 39, 329 ------------ 22

• ３． Kurokawa, H., (1987) Solar Phys., 113, 259 --------- 20

• ４ . Kurokawa, H. (1989) Space Sci. Rev. 51, 49 ------- 19

• 5. Kurokawa, H., Takakura, T., et al. (1988) PASJ, 40, 357 ------------------ 18

Ichimoto, K. and Kurokawa, H. (1984) Solar Phys. 93, 105 ---------- 69 回

Introduction: what is flare ?

• Preflare energy buid-up• Trigger• Energy release --- magnetic reconnection

– Heating– Particle acceleration– Mass ejection– Shock wave

• Energy transport– Nonthermal electron beam– Heat conduction– Chromospheric evaporation– Radiation

Energy buidup

Energy release – magnetic reconnection

Unified model (Shibata 1997)

Energy transport

Bright soft X-ray Flare loop Is a Consequence of chromosphericevaporation !

Neupert (1968) ApJ 153, 59

• obs. soft X-ray line + microwave in flares => “additional material, not originally at coronal temperature, is rapidly heated and elevated to high stages of ionization during the event”

Neupert effect

• Time derivative of soft X-ray intensity ~ hard X-ray intensity

Hard X-raymicrowave

Soft X-ray

Dennis and Zarro (1993) OK(80%)Lee et al. (1995) no Tomczak (1999) spatial info OK

Theory and numerical simulations of

chromospheric evaporation

Hirayama (1974)

• “Particles observed in the corona and the solar wind are evaporated from the chromosphere during the flare”

x

TTpv

2

5

0

2

5

0)(

xt

TR

p

t － 2/7 　∝ 　 T

= 　 const.

Evaporation cooling (Antiochos and Sturrock 1978)

Nagai (1980) Solar Phys.1D-Hydro-sim.

F ~ 3x10^{9} erg/cm^2/s

Nagai (1980)

F ~ 3x10^{9} erg/cm^2/s

Nagai (1980)

F ~ 3x10^{9} erg/cm^2/s

Nagai (1980)

F ~ 3x10^{9} erg/cm^2/s

Nagai (1980)

F ~ 3x10^{10} erg/cm^2/s Strong downflow ~ 40km/s

Fisher et al. (1985) ApJ thick target heating by nonthermal electrons

Scaling law (Fisher 1985)

7/2

9

7/2

2107

7/20max

0

103//10310

)/(

/

cm

L

scmerg

FK

FLT

LTF

Flare maximum temperature

Maximum velocity of evaporation upward flow

2/1

7

max

10/1000

35.2

K

Tskm

CV s

MHD Simulation of Reconnection with Heat Conduction and Chromospheric Evaporation

(Yokoyama and Shibata 1998, 2001)7/27/6 LBT

Reconnection heating = conduction cooling

Flare temperature scaling law（ Yokoyama and Shibata 1998 ）

2 B

LTVB A 2/4/ 2/72

7/6BT

7/27/6 LBT

Simulation of soft X-ray and radio observations

Prediction of Yokoyama-Shibata

1998

Observational evidence of chromospheric evaporation

Antonucci et al. (1982) SP 78, 107detected blue shift of evaporation upward flow

Antonucci et al. (1982)

Antonucci et al. (1982)

Ichimoto and Kurokawa (1984) SP

93, 105solved red asymmetry

problem

• “The spectroscopy of Ichimoto and Kurokawa (1984) represents the zenith of what has been achieved up to now by conventional photographic spectroscopy”

(Canfield et al. 1990)

Can red asymmetry be explained by absorbing material ?

Redshift cannot be explained byabsorbtion

Temporal variation of downward velocity in theflare emitting region

(Ichimoto and Kurokawa 1984)

● 　 wing shift x peak shift ○ 　 Halpha intensity

Ichimoto and Kurokawa (1984)

• H alpha red asymmetry (40-100 km/s) is is due to downward motion of the compressed chromospheric flare region produced by the impulsive heating by energetic electrons or thermal conduction

Canfield et al. (1990) H alpha + Hard X-ray confirm Ichimoto-Kurokawa, but show

also blue shifted H alpha emssion

Wuelser et al. (1992) ApJ 384, 341

• SMM X-ray + Sacpeak H alpha line

upflowing coronal material (as seen in Ca XIX soft X-rays) and downflowing chromospheric material (as seen in redshifted H alpha) appear simultaneously at the beginning of impuslive hard X-ray emission, with the total momenta of oppositely directed plasmas being equal to the observational uncertainties

Wuelser et al. (1992)

Nogami, Brooks, Isobe, Shibata,,,(2003-2004)

• We want to observe stellar flares with the scientific purpose similar to that of Wuelser et al. (1992)’s solar flare observations by using both Subaru and XMM-Newton

Further developments

• Wuelser et al. (1994)– Yohkoh-Mees – Upflowing coronal plasma and downflowing chromospheric plas

ma at the same locations, at footpoints of a soft X-ray loop– Footpoints are not heated by nonthermal electrons but by heat c

onduction

• Shoji and Kurokawa (1995)– Hida DST– Impulsive phase spectra of flares for Halpha, CaIIK, HeID3, NaI

D1,2, other metalic lines– Emitting region of chromospheric flare consists of two regions;– Thin fast downward moving layer, and stationary optically thick l

ayter (for metalic lines)

Latest paper

• Teriaca et al. (2003) ApJ 588, 596– SOHO/CDS, SacPeak, GOES

first quasi-simultaneous and spatially resolved observations of velocity fields during the impulsive phase of a flare, in both the chromosphere and upper atmospehre

Shimojo et al. (2001)evaporation occurs also in X-ray jets

(see also Miyagoshi and Yokoyama 2003)

Shimojo-Shibata (2000) ApJ

X-ray jets are evaporation flows(Shimojo and Shibata 2000)

Future Subjects

• Spectroscopic observatsions of flares should be done at Hida with DST as the most important priority projects in 2003

• H alpha red asymmetry of surges would be observed (at the footpoint of surges/X-ray jets)

• stellar flares observations will be interesting to detect evaporation flows

• Remaining puzzles: – blue shifts ?– Nonthermal electrons or thermal conduction ?

• Develop further MHD simulations with evaporation in 2D and 3D, incorporating effects of nonequilibrium ionization, nonthermal electrons, and radiative transfer

飛騨天文台観測論文引用ベスト１０

ADS 調べ： 2003 年 4 月２７日• 1. Ichimoto, K. and Kurokawa, H. (1984)

Solar Phys. 93, 105 ---------- 69 回• 2. Ichimoto, K., Kubota, J., et al. (1985)

Nature, 316, 422 -------------- 49• 3. Oda, N. (1984)

Solar Phys. 93, 243 ----------- 34• 4. Hanaoka, Y., Kurokawa, H., et al. (1994)

PASJ, 46, 205 ------------------ 28• 5. Ichimoto, K. (1987)

Solar Phys. 39, 329 ------------ 22

• 6. Kurokawa, H., (1987) Solar Phys., 113, 259 -------- 20 回

• 7. Kurokawa, H. (1989) Space Sci. Rev. 51, 49 ------ 19

• 8. Kawaguchi, I. (1980) Solar Phys. 65, 207 ----------- 19

• 9. Kitai, R. and Muller, R. (1984) Solar Phys. 77, 121 ------------18

• 10. Kurokawa, H., Takakura, T., et al. (1988) PASJ, 40, 357 ------------------ 18

• 11. Brueckner, G. E., et al. (1988) ApJ, 335, 986 --------------- 18 回

• 12. Kurokawa, H., Hanaoka, H., et al. (1987) Solar Phys., 108, 251 ------ 17

• 13. Tsubaki, T., et al. (1988) PASJ, 40, 121 --------------- 17

Al.1 Al 　Mg

温度が求ま

る

実際のデータで見てみましょう

温度は・・・

410)(

3 TnQkT

trad

2

25

0

2

103 T

nkLtcond

coolingmechanism

conductive cooling

２．２．２　理論から予測されるcooling

evaporation の 効果無し （密度一定）

evaporation の 効果有り　（密度変化）

t － 2/5 　∝ 　 T

(Antiochos and Sturrock , 1978)

詳細

詳細

t － 2/7 　∝ 　 T

conduction & evaporation

コロナ（密度　小）

彩層（密度　大）

evaporation により、ループ内の密度が上昇 する。

彩層蒸発

熱伝導が彩層へ

evaporation （彩層蒸発）

２．２．３．　理論と観測値の比較

フレア全体Local

－０．２８１ －０．１８７

t － 2/7 　 )∝( T

‐2/7 　 = 　‐０．２８６比較　その１（９７ / １

１ / ０６）

比較　その２（９４ / １１ / １３）

Local フレア全体

－０．２４１ －０．１７７

　　 Local フレア全体

97/11/06

　－０．２８１ 　－０．１８７

94/11/13

　－０．２４１ 　－０．１７７

t － 2/7 　∝ 　 T

(evaporation 効果有り )

286.072

とよく一致cooling が緩やか

観測値まとめ

２．４　結論

　　 Yohkoh の温度域（ ）で、　　　　

67 10~10~

（１） cooling mechanism 　⇒　conduction cooling（２） フレア全体解析 →　（１）より緩やか 　　 Local な解析　　　→　（１）とほぼ同じ

・戻る

2

7

2

0

3LT

nkTt

t － 2/5 　∝ 　 T

evaporation 無し

xTT

pv

2

9

0

25

0)(

xt

TR

p

t － 2/7 　∝ 　 T

= 　一定・戻る

evaporation 有り