The
Physics of the Heliopause
ISSI International Team
Abstract
This proposal is for an ISSI team to study the physics of the heliopause in the context of the Voyager observations, with the goal of maximizing the science return from the mission. The team consists of the Principal Investigators or their representatives from each of the functioning instruments on Voyager and a broad selection of theorists/modelers. The two Voyager spacecraft are exploring a totally uncharted region of space and will make the first crossings of the heliopause and enter interstellar space. This proposed team is timely because of the likelihood that the Voyagers will soon see (or may already be) seeing phenomena associated with the heliopause.
Full text of the proposal document (PDF).
Team members
John Richardson |
MIT |
Voyager Plasma instrument |
Vlad Izmodenov |
Moscow State University |
Theory and modeling, IBEX |
Rob Decker |
Johns Hopkins University |
Voyager Low Energy Charged Particle instrument |
Vladimir Florinski |
University of Alabama, Huntsville |
Theory and modeling |
Hans Fahr |
University of Bonn |
Theory and modeling, IBEX |
Roma Ratkiewicz |
Polish Academy of Sciences |
Theory and modeling |
Randy Jokipii |
University of Arizona |
Theory and modeling, organizer |
Merav Opher |
Boston University |
Theory and modeling |
Ed Stone |
CalTech |
Voyager Cosmic Ray Subsystem, organizer |
Tom Krimigis |
Johns Hopkins University |
Voyager Low Energy Charged Particle instrument |
Jim Drake* |
University of Maryland |
Theory and modeling |
* participated remotely
Project schedule
First meeting |
April 17-20, 2012 |
Second Meeting |
November 6-9, 2012 |
Third Meeting |
2013 |
Meeting 1 agenda
Tuesday, April 17, beginning at 9:00 AM
Ed Stone |
Observations overview |
Ed Stone |
CRS |
Ed Stone for Norm Ness |
Magnetometer |
Rob Decker / Tom Krimigis |
LECP |
John Richardson |
Plasma |
Hans Fahr |
IBEX results |
All |
Discussion |
Wednesday, April 18, beginning at 9:00 AM
Randy Jokipii |
Theory overview |
Merav Opher |
Magnetic reconnection in the heliosheath |
Vlad Izmodenov |
Effects of interstellar neutrals |
Roma Ratkiewicz |
MHD modeling |
Vladimir Florinski |
Cosmic ray transport |
Randy Jokipii |
Anomalous cosmic ray origin |
All |
Discussion |
Thursday and Friday, April 19-20: further discussion
Meeting 2 agenda
TBA
Publications
TBA
Topics to be addressed
Heliopause kHz radio source from electrostatic waves
Cutoff constrains number density of electrons
Is there a heliopause transition layer/region? How thick? Structure? Where?
Run simulations
Effects of neutrals, magnetic fields, modeling
Magnetopause analogs
Plasma depletion – reconnection?, physical cause
Simulate flow patterns and compare with observations
Can one model reproduce both V1 and V2 observations of flows, and magnetic fields? Time dependence?
Also V2 densities and thermal proton temperature
Prediction of 3-D structure and when V1/V2 are expected to cross heliopause. What will be seen?
Constraints on parameters and boundary conditions for model simulations (interstellar neutrals, latitudinal solar wind, etc)
Compare the different implementations of the heliospheric simulations for the same parameters
Long-term solar-cycle temporal variations of termination shock location at V1 and V2 now
Origin of the V1 plasma stagnation region
Models
Turbulence and large-scale instabilities at the heliopause
Propagation of disturbances into the heliosheath
Statistical description of disturbances
Galactic cosmic ray effects and gradients in the interstellar medium
Boundary conditions at the heliopause
Modulation outside the heliopause
Outer heliosheath fluctuations expected – can they significantly change the transport of cosmic rays?
Effects of the flow of ISM around the heliosphere on the GCR and ACR transport coefficients
Termination Shock Particle and Anomalous Cosmic Ray boundary condition at the heliopause – free escape? Anisotropies? Observable intensities?
Decreases in intensity as the Voyagers move outward
Compare with field direction and optimal regions for reconnect at the heliopause
Effects of cross-field diffusion/transport
Spectral evolution in the heliosheath
Magnetic field plasma, energetic particles in interstellar medium just outside of heliopause (magnitude, direction)
Energetic neutral atoms
ENAs from the heliotail direction?
Ribbon/belt connection
Connection between ENA and Voyager observations
Implications of Voyager observations for ENA
Comparison of ENA observations with the heliospheric simulations
Magnetic reconnection in the heliosheath/heliopause
Current-sheet thickness upstream and downstream of the termination shock?
Proton boundary layers, correlations with different instruments (esp. V2)
Direct observational tests of reconnection – e.g., V2 plasma turbulence
Observed magnetic field on V2 beyond 2009.5
Compare/contrast the two extreme model types now being considered
Particle transport and accceleration by magnetic reconnection
Acceleration of anomalous cosmic rays – energy issue
Predicted large anisotropies from anomalous cosmic-ray acceleration
Energetic-particle transport in reconnected bubbles
Inner-heliosheath magnetic field intensity related to flow speed