1. WG3 Session#1 Tuesday AM: What causes the energy dependence of Fe/O in large SEP events? Invited Speakers: Allan Tylka, NRL Mihir Desai, University of Maryland Jozsef Kota, University of Arizona Gang Li, University of California, Riverside Joe Giacalone, University of Arizona

2. Tylka & Lee emphasize the role of the seed population and shock orientation Basic thesis - injection threshold speed depends on shock normal angle i.e., quasi-parallel shock injects solar wind suprathermals and quasi-perpendicular shock injects flare suprathermals A simple ad hoc application of shock acceleration theory involving an injection threshold depending on shock geometry and an evolving shock reproduces the observations well. Surveys of ESP events confirm that the shock spectra and composition correlate well with that of a variable suprathermal seed population. However, the correlation between the energetic-particle spectra and local shock properties is poor. WG3 Session#1 Tuesday AM: Highlights

3. Numerical simulations of shocks moving through large-scale magnetic fluctuations indicate that the injection threshold is weakly dependent on shock-normal angle. Numerical models of diffusive acceleration at evolving CME-driven shocks appear to reproduce the double power-law spectra (as seen in some events with increasing Fe/O) and time-intensity profiles, but have not yet been compared with the abundances. WG3 Session#1 Tuesday AM: Highlights (cont.)

4. WG3 Session#1 Tuesday AM: What Next? Tylka & Lee model may be the first step toward understanding SEP compositional variability - however, several challenges remain Observations Goal: Understand the production of variable seed population for SEPs. Task:Expand the survey to include more events and characterize the 4-5 day solar activity preceding each SEP event over a broad range of energies (including low-energy suprathermals). Goal:Characterize shock properties while the CME was near the Sun. Task: Use solar observations to constrain the models – i.e. what is the field topology, where is the shock and what is its propagation direction, what are the properties of the magnetic turbulence, etc. (which are typically input as arbitrary shock parameters).

5. WG3 Session#1 Tuesday AM: What Next? Modelling/Theory: Goal: Understand the role of shock geometry (and other properties) on SEP abundance enhancements. Task:Combine more-realistic models of shock acceleration (including the effect of cross-field diffusion on the injection threshold) and shock evolution from the Sun to the Earth. Goal:What is the relevant physics that determines the energy spectra (i.e. what is responsible for the “average” that we see at 1AU) Task: Analyze the global CME/shock models in detail, perhaps by using a time-reversed “virtual spacecraft” starting at 1AU.

6. WG3 + WG1 Session #2 Tuesday PM: What causes the enhancements in 3He, and Ultra- heavy ions in impulsive SEP events? Invited Speakers: Glenn Mason, University of Maryland (Plenary session) Don Reames, NASA/GSFC Sam Krucker, SSRL, UC Berkeley Vahe Petrosian, Stanford University Randy Jokipii, University of Arizona Jim Miller, University of Alabama, Huntsville

7. There is convincing observational evidence that ultra-heavy ions (M>100) are associated with increases in He3 (which are associated with impulsive solar flares). Are these ions accelerated by the same process which accelerates the 3He? Current thinking is that 3He is accelerated by some form of resonant acceleration process (perhaps the well known stochastic acceleration). However, the standard models of stochastic acceleration cannot explain the existence of ultra-heavy ions. Extensions of the standard model may work, but are not presently quantitative. WG3 + WG1 Session #2 Tuesday PM: Highlights

8. Acceleration by gradual compressions can explain the abundance enhancements of ultra-heavy ions as a function of M/Q. However, it has not been successful in explaining the large abundance enhancements of 3He in impulsive solar-flare events. TRACE/RHESSI Xray observations of impulsive events (3He-rich event) show “jets” which are consistent with the picture of open magnetic field lines reconnecting with a closed-loop structure – a topology often invoked for stochastic-acceleration models. The “bimodal” distribution of Fe/O seen in a large number of SEP events (impulsive/gradual) is evident in a certain energy range (a few MeV/nuc.). It is not as clear in energies outside of this range. WG3 + WG1 Session #2 Tuesday PM: Highlights

9. What Next? Observations Goal:Further constrain acceleration mechanisms Task:What are the general conditions at the impulsive flare site? Theory/Modeling: Goal: Explain the existence of ultra-heavy ions AND 3He. Task: Are the two proposed acceleration mechanisms mutually exclusive? Can they operate together and what would be the resulting energy spectra? Are there other acceleration mechanisms? – Need CREATIVE IDEAS! WG3 + WG1 Session #2 Tuesday PM:

10. WG3 + WG1 Session #3 Wednesday AM: What is the relationshiip between the Type III radio emissions, and the suprathermal-through-relativistic electrons at 1 AU? Invited Speakers: Mike Reiner, NASA/GSFC Dennis Haggerty, Applied Physics Laboratory Jack Gosling, Los Alamos National Laboratory Paul Evenson, Bartol Research Institute Nariaki Nitta, Lockheed Martin, Palo Alto Hilary Cane, NASA/GSFC

11. Due to variations in the solar wind plasma density, Type III bursts that appear to extend to local plasma frequencies can also originate from remote locations. New analysis shows that the electron delays are not well correlated with the drift rate of radio emissions. This implies that the association between >40 keV electrons and Type III bursts is coincidence and that these electrons are not related to those that produce the Type III bursts. However, if there are two separate populations of electrons, then why are these higher energy electrons not associated with a Type III burst of their own? One possibility is that the electrons are scattered in the interplanetary medium en route to 1 AU. Another possibility is that these events are associated with complex multiple Type III bursts. WG3 + WG1 Session #3 Wednesday AM: Highlights & Points of Contention

12. Jack Gosling - Modulations and flux dropouts in impulsive ion events are reasonably correlated with those seen in suprathermal electrons (a few eV) - Acceleration, injection, and propagation of ions and electrons with similar speeds are governed by common physical mechanisms - However, these events are not necessarily accompanied by > 40 keV electrons Paul Evenson - Electron spectral shapes are independent of longitudinal separation - Electron spectra during short duration (impulsive) X-ray flares harden at higher energy - Electrons are injected instantaneously during these events Nariaki Nitta - Electron measurements and Type III bursts are used to constrain the timing and identify the solar sources of 3He-rich SEP ion events - TRACE/RHESSI measurements are used study the characteristics of the source regions - Use the PFSS model to locate open and closed field lines near the source regions WG3 + WG1 Session #3 Wednesday AM: Highlights & Points of Contention

13. Challenges Better solar wind density models to characterize the medium and understand the propagation of Type III bursts to determine their origin i.e., local or remote. If association is statistically significant then we need to WG3 + WG1 Session #3 Wednesday AM: Highlights & Points of Contention

14. This session will focus on investigating the origin of extreme solar and interplanetary events and their impact on geospace with a particular emphasis on the similarities and differences between the well-documented events of cycle 23 (e.g., Halloween 2003) and those observed during previous solar cycles. WG3 + WG1 Session #4 Thursday AM: Extreme SEP Events, their solar origin and impact on geospace

15. Invited Speakers: Christina Cohen, Caltech Nat Gopalswamy, NASA/Goddard Joe Mazur, The Aerospace Corporation Joel Mozer, Airforce Research Lab. Frank Toffoletto, Rice University What are the common features and differences between the extreme SEP events of cycle 23 and those observed during previous solar cycles? What are the key solar observations associated with these extreme events? How do such disturbances affect technological systems in geospace? How can existing datasets aid development of a framework that predicts the occurrence and potential impact of such events? WG3 + WG1 Session #4 Thursday AM: Extreme SEP Events, their solar origin and impact on geospace

16. WG3 Session#5 Thursday PM: Invited Speakers: Gerard Bond, Columbia University Ken McCracken, University of Maryland Leif Svalgaard, AFRL Vladimir Florinski, UC Riverside Long-Term Solar Variability: Effect on the Interplanetary Magnetic field, Galactic Cosmic Rays, and Earth’s Climate

17. There are strong correlations in the long-term records (10Be, sunspots, temperature, etc.). There appears to be a minimum in the 10Be record. This may imply a maximum modulation potential and may also be associated with a maximum heliospheric magnetic field. Large SEP events seem to be more prevalent during LOW solar activity. Considerable cosmic-ray modulation during the “grand minima” (Maunder, Dalton, etc.) WG3 Session #5 Thursday PM: Highlights

18. The Aa index prior to the 1950’s may be unreliable. The record can be corrected and it is found that it shows no long-term trend. Solar modulation of cosmic rays ~4000 years ago may have been affected by the Sun’s motion through a cold, dense interstellar cloud. A large spike in the 10Be record occurring in about 1460 may have been due to gamma rays from a supernova. WG3 Session #5 Thursday PM: Highlights

19. What Next? Observations Goal:What do the strong correlations mean? Task:Need solar physics input – i.e. what is happening on the Sun over a longer time scale (total solar irradiance)? Theory/Modeling: Question: How can we understand the occurrence of large SEP events and enhanced modulation during low solar activity? WG3 Session #5 Thursday PM: