WG3 Session#1 Monday PM :

WG3 Session#1Monday PM:

The acceleration of rare tracer ion species like 3He2+ and 4He+ at CME-driven interplanetary shocks at ACE provides clear evidence that the seed population originates from the ubiquitous suprathermal tail rather than the more abundant solar wind peak.

This session brings together data sets from ACE, Wind, Ulysses, SoHO, and Cassini to characterize key properties of the suprathermal tail and unravel some of its mysteries.

Critical for understanding particle acceleration at CME-related ESP and SEP events

Sources of Suprathermal Ions in the Solar Corona and the Interplanetary Medium

(adapted from Desai et al., 2001 and Kucharek et al., 2003)

The Suprathermal Tail

Properties are not well understood; known contributors

• Heated solar wind

• Interstellar and inner source pickup ions

• Prior solar and interplanetary activity

• Planetary bow shocks and magnetospheres

• Other?

(Mewaldt et al., 2001 AIP conference Proceedings 598, 165)

~2-10 times the solar wind speed

Solar Wind Abundance Solar Wind Abundance RatiosRatiosSolar Wind Abundance Solar Wind Abundance RatiosRatios

• Von Steiger et al., (2000, JGR , vol. 105, 27217)Von Steiger et al., (2000, JGR , vol. 105, 27217)

C/O and Fe/O @ 100 keV/nC/O and Fe/O @ 100 keV/n

• Suprathermal C/O and Fe/O are highly variable and exhibit solar cycle effects

• Solar wind abundances do not exhibit strong solar cycle effects

WG3 Session#1Monday PM:

Sources of Suprathermal Ions in the Solar Corona and the Interplanetary Medium?

Suprathermals show ~100 times more variation in intensity than solar wind density -- may be an important factor in CME-shock

acceleration

(Mason et al., 2005; Desai et al., 2005)

Proton intensities @2 MeV and 20 MeV are not well correlated with CME speed

Critical issue for LWS and Exploration Initiative

Basic Correlations of CMEs/SEPsBasic Correlations of CMEs/SEPs

Kahler JGR, 2001

Invited Speakers:• Matthew Hill, University of Maryland• George Ho, Johns Hopkins University/Applied Physics Laboratory• Thomas Zurbuchen, University of Michigan• Nathan Schwadron, Southwest Research Institute• Lennard Fisk, University of Michigan

• What are the main sources of ions in the suprathermal tail?

• How do the relative contributions of these sources vary in time and space?

• What causes these variations?

• How do these variations affect CME-related ESP and SEP events?

• What measurements and theoretical studies are needed to make further

progress?

WG3 Session#1Monday PM:

Sources of Suprathermal Ions in the Solar Corona and the Interplanetary Medium