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