ESPM-13 Curdt 1

Helicity in spicules andexplosive events

Werner Curdt 1), Hui Tian 2)

1) Max-Planck-Institut für Sonnensystemforschung2) High Altitude Observatory

ESPM-13 Curdt 2

Helicity in spicules andexplosive events

Outline:

Motivation EE properties Observational details The problem with EE Helicity in small-scale phenomena Helicity in EE & consequences Conclusion

ESPM-13 Curdt 3

„Explosive Events“:

Doppler motion: ± 50 ... 150 km/s duration 60 ... 200 s size 1500 ... 2500 km burst rate several minutes -1

birth rate 2500 per second temperature transition region lines

Dere 1984

Innes 1997Chae 1998Madjarska 2002Ning 2004Teriaca 2004...

„Explosive Events“:

Doppler motion: ± 50 ... 150 km/s duration 60 ... 200 s size 1500 ... 2500 km burst rate several minutes -1

birth rate 2500 per second temperature transition region lines

model

ESPM-13 Curdt 4

AR 11124 onNov 16, 2010

SUMER slit onSDO images

ESPM-13 Curdt 5

lambda / nm

spec

tralr

adia

nce

Si III Lyman-α

●S

I

●S

I

●S

I

●S

I

●S

I ●S

I ●S

I

ESPM-13 Curdt 6

- rapid „switch on“- no accelaration- Dopplerflow ± 40 km/s- continues over 4 minutes- double-peaked lightcurve- τ=2πr / v ≈ 150 s

●●●

●

● ●

ESPM-13 Curdt 7

●●●

●

● ●

- rapid „switch on“- no accelaration- Dopplerflow ± 35 km/s- continues over 4 minutes- double-peaked lightcurve- τ=2πr / v ≈ 160 s

ESPM-13 Curdt 8

... it is difficult to explain the lack of apparent motion of such high-velocity events ...

Dere et al. 1984

... the event ... does not continueto spread in size ... and seems to stay very localized

Innes et al. 1997

ESPM-13 Curdt 9

ESPM-13 Curdt 10

O V 629 Åv = -30 ... + 30 km/s CDS tornados (Pike 1998)

ESPM-13 Curdt 11

φ = 0° 30° 45° 90°

ESPM-13 Curdt 12

Observation on Nov 19, 2010 model, φ = 45°

S I

S I

φ = 45°

ESPM-13 Curdt 13

slit of 0.3“dispersed emission of EEinclinedby several pixels !

+40 km/s -40 km/s

Rompolt 1975:Spectral features to be expectedfrom rotational ... motions in fine solar structures

ESPM-13 Curdt 14

vlos = 40 km/svp = 56 km/sr =1000 kmac = v2 / r = 3.2 km/s2 ≈ 10 a

The centripetal acceleration exceeds the solar gravityby an order of magnitude !

Pasachoff 1968

ESPM-13 Curdt 15

helicity in CMEs

helicity in coronal bright points and X-ray jets(Tian 2008, Kamio 2009, Liu 2011)

31 out of 79 EUVI jets show helical motion (Nisticó 2009)

ESPM-13 Curdt 16

Kamio et al. 2010

XRT

STEREO 304

ESPM-13 Curdt 17

Concluding remark:

(1) case study vsstatistical result

(2) IRIS 10 faster(3) source of helicity ?(4) photospheric nature ?

Curdt & Tian 2011