PROBA 2 Guest Investigator project (2010-2012)PROBA 2 Guest Investigator project (2010-2012)

EUV imaging of the solar EUV imaging of the solar corona and study of slow solar corona and study of slow solar

wind streams wind streams

V. Slemzin. Slemzin11, L. Harra, L. Harra22, S. Kuzin, S. Kuzin11, A. Urnov, A. Urnov11, F. , F. GoryaevGoryaev11, , 11LPI, Russia, LPI, Russia, 22MSSL/UCL MSSL/UCL

PROBA 2/SWAP teamPROBA 2/SWAP team

The goal of the study :

To localize sources of the quasi-stationary slow solar wind.

Method:

Some of the sources may be localized by outflows from active regions detected by the Doppler spectroscopy, their signatures in the corona co-aligned with open field lines and imprints in the slow solar wind.

Coronal signatures: fan rays at the disk and extended coronal rays at the limb.

First part of the study (2010-2011) :

1) imaging of the solar corona with SWAP

2) detection of outflows at the disk with Hinode/EIS

3) identification of coronal signatures of outflows

4) search of imprints of outflows in the solar wind data.

1. Wide FOV imaging of the inner corona with 1. Wide FOV imaging of the inner corona with SWAPSWAP1. Paving ±10’

2. Summation of 80-90 images in each position Cadence 30 s Full time of observation ~ 3h

3. Straylight subtraction using the eclipse images

4. Combination of a mosaic image

Straylight model(linear Log fit to the radial distribution at R>2Rsun)

08 July 2010

20 October 2010 21 October 2010

8 July 2010 1.94 Rsun

01 Dec 2010 2.10 Rsun

The length of coronal rays is defined by Ne at the base and radial velocity.

If V≥ 60 km/s, the rays are not seen at R>1.5Rsun due to Doppler dimming

AIA 171 September 12, 2011 SWAP 174

AIA vs AIA vs SWAPSWAP

AIA 171 A:- Limited FOV- Higher resolution

SWAP 171 A:-Wider FOV- lower straylight

2. 2. Detection of outflows with Hinode/EISDetection of outflows with Hinode/EIS

Out

flow

do

wnf

low

EIS, October 15, 2010

Zoomed SWAP and PFSS in the EIS FOV

AR 11112

SWAP

PFSS

3. Coronal rays as main signatures of outflows3. Coronal rays as main signatures of outflows

SWAP, March 23, 2011

SWAP April 6, 2011

Outflow region

EIS, March 23, 2011

EIS, April 4, 2011

Outflow region

AR 11176

PFSS April 6, 2011

LASCO C2, April 6, 2011

LASCO and SWAP polar images at W-limb (April 6, 2011)

The streamer corresponds to the outflow position at the limb

4. Imprints of outflows in the solar wind data4. Imprints of outflows in the solar wind data(October 2010)(October 2010)

Positions of STEREO A , - B , ACE and WIND on 2010-10-15 12:00 UT

ACE/WIND

Oct 15, 2010

Oct 13-14Δt=4.3d

Oct 18-19Δt=4.2d

Oct 26-29Δt=6.3d

Variation of the solar wind flux correlates with temporal evolution of the AR

ConclusionIt was shown that outflows in active regions detected at the disk in

the Fe lines with Texc~1 MK can produce extended coronal

structures coaligned with open field lines and imprints in the slow

solar wind.

Publication: Slemzin , Harra et al. Submitted To Solar Phys.

Two main advantages of SWAP to detect coronal signatures of

the plasma flows:

1.Large field of view

2.Wavelength band 174 A (FeIX-X) is optimal to see structures with

T~1MK responsible for plasma transit from the Sun to the solar wind

. It is confirmed by domination of the FeXI ions in the solar wind

(Habbal et al. 2007, 2010)

N

S

0

180

90270

Second part of the study (2011-2012):Second part of the study (2011-2012):

Long term evolution of the EUV corona. Long term evolution of the EUV corona. Comparison of coronal and magnetic synoptic Comparison of coronal and magnetic synoptic

mapsmaps

Polar movie of the corona during 1 Polar movie of the corona during 1 rotationrotation

Variation of the synoptic maps of the Variation of the synoptic maps of the corona with distance R=1.00 – 1.67 corona with distance R=1.00 – 1.67

RsunRsun

3. Comparison with the WSO synoptic maps of magnetic field.

Photospheric field

R=1.00 Rsun

R=1.66 Rsun

Source surface at 2.5 Rsun

Lee et al. 2011:In the min of 22-23 cycles SS is located at 1.9 – 1.5 Rsun