BS ISO 17520:2024
Space environment (natural and artificial). Cosmic ray and solar energetic particle penetration inward the magnetosphere. Method of determination of the effective vertical cut-off rigidity

Standard No.

BS ISO 17520:2024

Release Date

2024

Published By

British Standards Institution (BSI)  GB  /  BSI

Latest

BS ISO 17520:2024

Introduction

Technical Overview of Cosmic Ray Penetration Standards

The BS ISO 17520:2024 standard establishes methodologies for calculating effective vertical cut-off rigidities (EVCR) of charged particles in near-Earth space. This revision supersedes the 2016 edition with key updates including:

Feature	2016 Edition	2024 Edition
Reference Epochs	2005-2015	2005-2020
IGRF Models	Basic tables for 3 epochs	Added 2020 epoch data
Accuracy	±2%	Enhanced validation

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Core Calculation Methodology

The standard specifies trajectory tracing techniques for negatively charged particles using:

• IGRF models for internal geomagnetic fields
• Tsyganenko models for external magnetospheric effects

Critical parameters include:

• Geographic coordinates (λ,φ)
• Altitude range: 250-20,000 km
• Kp-index (0-9 scale)
• Local time (T)

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Implementation Guidelines

For operational applications:

1. Use Tables B.1-B.4 for IGRF reference values
2. Apply altitude correction via Formula (B.2)
3. Calculate disturbance effects using Equations (B.3-B.6)

Practical Example

For a satellite at 1,000 km altitude (λ=10°, φ=0°) during moderate geomagnetic activity (Kp=3):

• Base R₀ = 12.684 GV (from Table B.4)
• Altitude-adjusted R₀ = 12.421 GV
• Final R_eff = 10.751 GV (per Table B.5 validation)

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Technical Evolution

The standard reflects 8 years of magnetospheric research advancements:

• Improved correlation (r=0.998) with 1990 reference data
• Extended validity to 0.2 GV lower limit
• Enhanced analytical equations for disturbance modeling

BS ISO 17520:2024 history

• 2024 BS ISO 17520:2024 Space environment (natural and artificial). Cosmic ray and solar energetic particle penetration inward the magnetosphere. Method of determination of the effective vertical cut-off rigidity
• 2016 BS ISO 17520:2016 Space environment (natural and artificial). Cosmic ray and solar energetic particle penetration inward the magnetosphere. Method of determination of the effective vertical cut-off rigidity

Standard and Specification