GEANT-4/Spenvis User Meeting
November 2006
Solar Energetic Particle Solar Energetic Particle Modelling Activities at ESAModelling Activities at ESA
A. Glover1, E. Daly1,A. Hilgers1, SEPEM Consortium2
1. Space Environments and Effects Section ESA/ESTEC, Noordwijk, The Netherlands,
2. BIRA-IASB, Univ Barcelona, Spain, UCL, Leuven, Belgium, Univ Southampton, UK QinetiQ, UK
GEANT-4/Spenvis User Meeting
November 2006
ContentsContents
• Background– SEP Events– Effects – Existing Models
• The SEPEM Project– Databases– Tools based on existing models– New model development– Helioradial variation
• Planning• Conclusions & future
GEANT-4/Spenvis User Meeting
November 2006
SEP EventsSEP Events● Impulsive: Solar flare accelerated particles (no shock)● Mixed: Flare + Coronal/interplanetary shock accelerated particles● Gradual: (Coronal and interplanetary) shock-accelerated particles
Impulsive (left) and Gradual (right) SEP event measured by ACE/EPAM (2x low energy channels) and IMP-8/CPME (2x high energy channels).
GEANT-4/Spenvis User Meeting
November 2006
Example SEP Effects Example SEP Effects • Cumulated damage Cumulated damage
(ionisation, (ionisation, displacement, etc…) displacement, etc…) e.g., on electronic e.g., on electronic and optical and optical components.components.
• Single Event Upsets.Single Event Upsets.• Background in Background in
detectors.detectors.
GEANT-4/Spenvis User Meeting
November 2006
Engineering requirementsEngineering requirements
• Integrated proton fluence over time period (months to years) at given energy (direct effect would be even better).
• Frequency of occurrence of particle flux above given value over time period (seconds to years) at given energy, given ion mass.
• Function of location (geo- and interplanetary space)
• Function of time (minutes to years).
GEANT-4/Spenvis User Meeting
November 2006
Available Models and Available Models and Standards WorkStandards Work• JPL-91: “de-facto” & ECSS-E-10-04 standard
– Suitable for fluence assessment– Re-evaluations by Rosenqvist et al. & Glover et al.
• ESP (Xapsos): gaining rapid acceptance – Fluence and peak flux, extreme value approach
• CREME-96– Based on October 89 “worst case” ; suited to SEE– Not worst case; no indication of statistical “rank”
• “Nymmik/ISO– Correlation of event rate with SSN– Reevaluation of data sets
GEANT-4/Spenvis User Meeting
November 2006
SEPEM StudySEPEM Study
• New 2 year study• Consortium led by BIRA-IASB &
including Univ. Barcelona, U C Leuven, Univ. Southampton and QinetiQ
• Wide ranging study geared towards updating existing models and developing new models and tools
• Started September 2006
GEANT-4/Spenvis User Meeting
November 2006
Goals of the SEPEM StudyGoals of the SEPEM Study
• Create new engineering models to address ESA’s future needs including: – Ingestion of new data– Enable automated model update– Go beyond mission integrated fluences for
given confidence level: new products e.g. peak flux stats, duration of high flux periods…
– Incorporate databases of ion species– Include new understanding of generation
mechanisms– Investigate helio-radial variation using physics
based shock—acceleration models
GEANT-4/Spenvis User Meeting
November 2006
Requirements PhaseRequirements Phase
• Review of engineering requirements currently underway
• Requirements will be input to roundtable meeting on SEP Modelling 12-14th Feb, Southampton, UK
• E.g. requirements… – Estimate dose over timescale mths/yrs as
function of heliocentric distance– Estimate maximum differential flux at given
energy– Estimate frequency of occurrence of
differential flux above given threshold– …
GEANT-4/Spenvis User Meeting
November 2006
Basic ingredients for modeling a SEP event
A good description of the shock propagationshock propagation
A realistic simulation of the particle particle transporttransport
A continuous survey of the shock-acceleration mechanisms and injection injection of energetic of energetic particlesparticles, as the shock expands.
Interplanetary Magnetic Field
COBPOINT
Observer
Energetic particles
Cobpoint displacement
A key concept: Connecting with the
Observer Point
Propagating front of the interplanetary
MHD shock
0.8 AU
Observer
1
43
2
Helioradial Dependence: Helioradial Dependence: Shock-plus-particle modelShock-plus-particle model
1 AU
GEANT-4/Spenvis User Meeting
November 2006
SOLPENCOSOLPENCO
• Solar particle engineering code– Step towards an operational tool aiming to
predict flux & fluence profiles of SEP events– Database of 448 scenarios at 1AU & 0.4AU
for p+ energies 0.125-64MeV– User interface allowing rapid acquisition by
interpolation of flux & fluence profiles of upstream part of SPE event for given interplanetary scenario
– Estimates transit time & speed of IP shock
GEANT-4/Spenvis User Meeting
November 2006
E35 1200 W10 [l08TN] 2 MeV W28 1000 W10 [l02TN] 2 MeV
Flux Flux
Fluence Fluence
Shock arrival Shock arrival
SOLPENCO: Example SOLPENCO: Example OutputsOutputs
GEANT-4/Spenvis User Meeting
November 2006
Updating SOLPENCOUpdating SOLPENCO
• Original shock-plus-particle model:– MHD shock propagation model (Wu et
al.: Solar Phys. 84, 395, 1983– Particle propagation model (Lario et
al.: ApJ 509, 415, 1998)
• Update to include: – Improved wind model: inner boundary
closer to Sun, different wind velocities, extend results out to 2AU
GEANT-4/Spenvis User Meeting
November 2006
Upcoming ActivitiesUpcoming Activities
• SPE modelling review – identify other candidate models
• Review of available datasets – generate comprehensive database of available SEP data
• Development and validation of effects model at 1AU
• Development and validation of heliocentric dependence of effects
• Produce guidelines for use and update• Propose suitable outputs as potential standard
GEANT-4/Spenvis User Meeting
November 2006
Last Word…Last Word…
• Need for community involvement in ISO standards process to propose a consensus approach;– Example first steps might be:
•Standardize data sets to employ ( GOES (which ones?); IMP (which instruments?) )
•Standardize event selection methods