GEANT-4/Spenvis User Meeting

1
Solar Energetic Particle Modelling Activities at
ESA

• Glover1, E. Daly1,A. Hilgers1,
• SEPEM Consortium2
• Space Environments and Effects Section ESA/ESTEC,
  Noordwijk, The Netherlands,
• BIRA-IASB, Univ Barcelona, Spain, UCL, Leuven,
  Belgium, Univ Southampton, UK QinetiQ, UK

2
Contents

• Background
• SEP Events
• Effects
• Existing Models
• The SEPEM Project
• Databases
• Tools based on existing models
• New model development
• Helioradial variation
• Planning
• Conclusions future

3
SEP 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).
4
Example SEP Effects

• Cumulated damage (ionisation, displacement, etc)
  e.g., on electronic and optical components.
• Single Event Upsets.
• Background in detectors.

5
Engineering 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).

6
Available Models and Standards 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

7
SEPEM 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

8
Goals of the SEPEM Study

• Create new engineering models to address ESAs
  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 shockacceleration models

9
Requirements 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

10
Helioradial Dependence Shock-plus-particle model

• Basic ingredients for modeling a SEP event
• ? A good description of the shock propagation
• ? A realistic simulation of
• the particle transport
• ? A continuous survey of
• the shock-acceleration
• mechanisms and injection
• of energetic particles,
• as the shock expands.

1 AU
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SOLPENCO

• 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

12
SOLPENCO Example Outputs
Shock arrival
Shock arrival
E35 1200 W10 l08TN 2 MeV W28 1000
W10 l02TN 2 MeV
13
Updating 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

14
Upcoming 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

15
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