Introduction to the Physics of the Sun, Heliosphere and Space Weather 3

Volker Bothmer1 and Jörg Büchner2

Institute for Astrophysics, University of Göttingen (IAG) Max-Planck-Institute for Solar System Research (MPS), Kaltenburg-Lindau

Lectures WS 2010/2011 26 October 2010 – 15 February 2011

INTRODUCTION TO THE PHYSICS OF THE SUN, HELIOSPHERE AND SPACE WEATHER 3. The solar wind The existence of the solar wind was deduced theoretically from HD equations by Parker in 1958

The advent of the space age: In 1962 Mariner 2 records the solar wind

Dylan, 1962

Neugebauer und Snyder (1962) Solar wind sampling on moon – Apollo 11, 20 July 1969

Images: NASA II. 6 Uni Göttingen WS 06/07 Solar wind characteristics at 1 AU based on Helios 1,2 measurements

Plasma bulk velocity V 300 – 800 km/s

-3 Proton density NP 10 cm 4 Proton temperature TP 4 · 10 K 5 Electron temperature TE 1.5 · 10 K Magnetic field strength B 4-5 nT Helios-Orbit: Plasma composition 95% Protons, 4% Helium 0.29 – 1 AU ions, very few heavy elements, same number of Sun free electrons (quas neutrality)

Earth Silber und Gold im Sonnenwind ... Solar wind characteristics at 1 AU based on Helios 1,2 measurements

Plasma bulk velocity V 300 – 800 km/s

Earth

Observations of fast and slow solar wind streams – Helios 1, 1976

Alfvén waves and small-scale structures Marsch, 1991 Basic characteristics of fast and slow solar wind streams

The solar wind carries the photospheric/coronal magnetic field into space

The Parker Spiral of the Interplanetary Magnetic Field (IMF)

Observations of fast and slow solar wind streams – Helios 1, 1976

Sometimes the solar wind ‚disappears‛

Heliospheric 3-D solar wind structure during solar minimum – Ulysses measurements

Solar Probe Plus to come

until 2018 (< 10 RS)

McComas et al., GRL 1998 SOHO/EIT/SUMER: Doppler-shifts of coronal emission lines: High speed solar wind outflow from chromospheric (supergranular) network

Hassler et al. 1999

Solar wind from ‚coronal funnels‛

Tuetal. (2005)

“Doppler shifts” @ 20Mm correlate with structures of the solar magnetic field. Coronal Jets as Manifestations of Photospheric Variability on Small-Scales Missions to achieve new scales: Sunrise, Solar Orbiter

Hinode Reconnection Untwisting Small-Scale CMEs

Bothmer and Nisticò (2009); Nisticò et al. Patsourakos et al., ApJ L. (2008); Nisticò et al. (2009) Innes et al. (2008) (2009) Pariat et al. (2008) Moreno Insertis et al. (2008); Yokoyama & Shibata (1996) STEREO high res. Campaign, 171 Å, 75 seconds

Heliospheric 3-D solar wind structure during solar minimum – Ulysses measurements

Solar Probe Plus to come

until 2018 (< 10 RS)

McComas et al., GRL 1998

Alfvén’s Ballerina Model of the Inner Heliosphere

Co-rotating Interaction Region (CIR)

Alfvén, Rev. Geophys. Sp. Phys. 1977 STEREO Orbit Overview

Today: STEREO A (84°), STEREO B (79°) Sun Centered Imaging Package ( SCIP) und SESAMe The SECCHI-Suite consists of five individual optical telescopes observing the Sun and Heliosphere in EUV and WL

COR 1

EUVI

COR 2

HI 2 HI 1

Howard et al., Spa. Sci. Rev. 2008 Imaging the Sun and Heliosphere – New Horizons from SECCHI

Angelo Secchi (1818-1878) STEREO/SECCHI/HI 2 A,B Panorama

HI FOV Geometry and WL Sensitivity

Basic Parameters HI-1 HI-2 Direction of Centre of 14 degrees 53.7 FOV degrees Angular Field of View 20 degrees 70 degrees Angular Range 4-24 18.7-88.7 degrees degrees Image Pixel Size 70 arcsec 4 arcmin Spectral Bandpass 630-730 400-1000 nm nm Nominal Image 60 min 120 min Cadence

-15 -16 Brightness Sensitivity 3 x10 Bo 3x10 Bo (Bo = solar disk) < >

Harrison et al., Sol. Phys. 2008; from Socker et al. (2000) First Optical Detection of a Fast Solar Wind Stream at Earth with HI 2 B – July 2007

7/19/07 16:10UT 7/20/07 6:10UT

Sheeley et al., ApJ 2008 Correlation of STEREO Remote-Sensing Observations with Solar Wind Measurements

Sheeley et al., ApJ 2008; Rouillard et al. 2008

STEREO/SECCHI has imaged for the first time Alfvén’s Ballerina

Co-rotating Interaction Region (CIR)

Alfvén, Rev. Geophys. Sp. Phys. 1977 Sample of HI 1 Background Substracted Movies That Reveal Various Outward Moving Features – CMEs, Blobs, Recurrent Solar Wind Flows

HI 1 A

Collaboration with J. Davies, C. Davis, RAL

The solar wind interacts with the objects of the solar system

Cosmic Rays

Ulysses

Messenger and Venus Express Mercury and Venus

Mars Rosetta Phoenix Comets and Planetoids

Moon and Earth Zodiacal Light – Interplanetary Dust Comet F1 Loneos – SECCHI HI 2 A: Observation of multiple Tail Disruptions in October/November 2007 Comet Encke – First Observation of a Comet Tail-Disruption by a CME - HI 1 A, April 20, 2007

Period: 3.3 years; Perihel: 0.338 AU ~42·106 km (0.28 AU) Distance to STEREO A: 0.76 AU

Similar to geomagnetic substorms: Plasmoid disconnection through magnetic reconnection

Vourlidas et al., ApJ 2007 Impact of the Solar Wind on Earth‘s Magnetic Field The Earth‘s magnetosphere jitters like a Flag in the Wind

Goodrich et al. 1997 Fast solar wind from coronal holes as causes of increased geomagnetic activity and medium

  V  B2 sin 4 ( ) SW IMF 2 storms (up to about Kp 7+)

Bothmer & Zhukov (2006) Correlation between V∙B (SW) and Ap (27 day averages) – 1964 to present Fast Interplanetary Shock Measured by Helios 1 in 1978

All Helios 1 Directed CMEs with a Speed >400 km/s in the FOV of the Solwind Coronagraph Caused a Shock at Helios 1!

Sheeley et al., JGR, 90, 1985 Correlation between V∙B (SW) and Ap (27 day averages) – 1964 to present J. Bartels – „Musical Diagram‚

The “musical diagram” of geomagnetic activity, introduced by J. Bartels (after 1932)

41 Geomagnetic activity in 2010 Merkur

Venus Stellar Winds

HST view February 1995. Arcing structure is stellar bow shock about half a light-year across, from star L.L. Orionis's wind colliding with the Orion Nebula flow. Click for much larger image. Courtesy NASA, Hubble Heritage Team (STScI/AURA). The Dynamic Corona Observed with SOHO/LASCO/EIT during December 1999 to January 2000

SOHO has observed >10,000 CMEs during 1996-2007

Coronal Mass Ejections (CMEs) occur on variable spatial- and time-scales.

Courtesy: B. Podlipnik