ISO 17520:2024 宇宙環境（自然環境と人工環境） | ページ 2

Foreword

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The committee responsible for this document is ISO/TC 20, Aircraft and space vehicles, and Subcommittee SC 14, Space systems and operations.

This second edition cancels and replaces the first edition (ISO 17520:2016), which has been technically revised.

The main changes are as follows:

• basic tables for epoch 2015 and 2020 calculated using IGRF model are added.

Introduction

This document describes principal requirements for determination of the effective vertical cut-off rigidity of penetration of charged particles inward the Earth's magnetosphere. This model provides for calculations of cut-off rigidity in arbitrary point of the magnetosphere at given local time. The document is applicable for calculating the particle penetration by any of the component of interplanetary charged particles (galactic, solar, and anomalous) with rigidities above 0,2 GV. The model satisfying these requirements depending on geomagnetic disturbances described by the K_p-index is presented in Annex B. The main goals of the present standardization for the determination of the effective vertical geomagnetic cut-off rigidities are as follows:

• provide an unambiguous procedure for calculation of the cut-off rigidities inside of the Earth’s magnetosphere reflecting dependences on geomagnetic disturbances and local time;
• provide means of estimation of the impact of charged particle fluxes in interpretation and analysis of space experiments.

1 Scope

This document describes the effective vertical cut-off rigidities of charged particles for near-Earth space and establishes principal requirements for their calculation based on different models of Earth’s geomagnetic field.^[1] The techniques are useful for determination of penetrating into the Earth's magnetosphere by charged particle fluxes, as well as for test and estimations of the impact on spacecrafts and other equipment in the near-Earth space.

2 Normative references

There are no normative references in this document.

3 Terms and definitions

For the purposes of this document, the following terms and definitions apply.

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

3.6

particle magnetic rigidity

R

value related to a particle’s momentum and its charge, calculated by: R = pc/Z

(1)

where

	p	is the particle momentum;
	c	is the speed of light;
	Z	is the particle charge (3.5)

Note 1 to entry: The magnetic rigidity of protons and nuclei is related to the particle's energy in accordance with Formula (2).

(2)

where

	E	is the kinetic energy in GeV/u;
	A	is the particle's mass in Dalton (atomic mass unit);
	M0	is the rest mass of proton equal to 0,931 GeV

Bibliography