Session #8: Corotating Interaction Regions and the Connection Between Their Trailing Edge and Energetic Particle Acceleration at 1 AU Organizers: Robert W. Ebert (SwRI), Lan K. Jian (NASA-GSFC/UMCP), Joe Borovsky (SSI/UM) Time: Thursday AM/PM Place: Grand Ballroom C

Recap – 2012 Session Are 1 AU CIR suprathermal and energetic particles accelerated locally? Ions are accelerated locally near the trailing edges of well-formed CIRs Open Question: Ions in weak CIRs are non-local, acceleration site is not certain=>multi-Point observations + modeling may help pinpoint the site How are these particles accelerated? Is a shock required? Local acceleration depends on the strength of the CIR, regardless of the presence or absence of a reverse shock. How do the plasma and field conditions at 1 AU influence ion acceleration? Peak He intensity depends on magnetic compression ratio, no dependence above ~0.8 MeV/nuc  Indicates an upper energy limit of ~0.8 MeV/nuc for local acceleration at 1 AU. Does the current interpretation provide a consistent picture for the acceleration and transport of CIR-associated particles seen at 1 AU? Not really.. Even in weak compression regions, spectra do not roll-over as expected from the Fisk and Lee model, thus ions below ~1 MeV/nuc are unlikely to come from shocks at ~3-5 AU.  

2013 Session The properties of CIRs and high speed streams with a Main Focus: The properties of CIRs and high speed streams with a focus on their trailing edges and the physical processes ongoing there. (2) Particle acceleration at CIRs and the role of their trailing edge in accelerating energetic particles near 1 AU.

Session – Part I (Thursday AM) Discussion Topics: A comparison of pseudostreamer and helmet streamer CIRs. (2) Plasma properties on the leading edge versus the trailing edge of CIRs and high speed streams. (3) Turbulence and Alfvénic structures in trailing edge plasmas.

Part I - Invited Speakers AM1: Ian Richardson (CRESST/UMd/GSFC) Title: The Interaction of Slow Solar Wind and High Speed Streams and the Formation of CIRs AM2: Chuck Smith (UNH) Title: Turbulence Associated with CIRs

Session - Part I Time from CIR trailing edge [Hrs.] from Borovsky (2013) Time from CIR trailing edge [Hrs.]

Session – Part II (Thursday PM) Topic: Understand the origin of energetic particles associated with CIRs at 1 AU Existing Theory: Particles are accelerated at CIR shocks between ~3-5 AU and are transported back to 1 AU along the Parker spiral. Particles can be accelerated in compression regions near 1 AU. Observational Picture: Clear evidence of suprathermal ions (< 1 MeV/nucleon) being accelerated at CIRs with a reverse shock or strong compression at 1 AU. Seed populations and acceleration sites of non-local particles are uncertain. Main Focus: Seed populations: bulk solar wind or suprathermal tail. Origin of non-local particles. Modeling CIR particle acceleration and transport.

Part II - Invited Speakers PM1: Glenn Mason (JHU/APL) Title: Particle Sources and Acceleration in CIRs PM2: Gang Li (UAH) Title: Particle Acceleration and Transport in CIRs

Session - Part II Use spectral form from Fisk & Lee (1980) to estimate source location of CIR energetic particles at 1 AU.

Abstracts  10 submitted  Topics include: Radial evolution of CIR magnetic structures between Earth and Ulysses. Stream interaction regions without sector boundary crossings associated with pseudostreamers. Acceleration of > 35 keV ions in CIRs at 1 AU – ISEE-3. Modeling the pick up propagation in corotating compression regions inside 1 AU. Charge state signatures in stream interaction regions.

Time: Thursday AM (9:45 – 12:45) Place: Grand Ballroom C Thursday PM (14:00 – 17:00) Place: Grand Ballroom C