Cosmic Rays and Space Weather Lev I. Dorman



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Cosmic Rays and Space Weather
Lev I. DORMAN
Israel Cosmic Ray Center and Emilio Segre' Observatory, affiliated to Tel Aviv University, Technion and Israel Space Agency (P.O.Box 2217, Qazrin 12900, ISRAEL); e-mail: lid@physics.technion.ac.il, lid1@ccsg.tau.ac.il / fax: 972-4-6964952 / tel. 972-4-6964932

IZMIRAN, Russian Academy of Science (Troitsk 142092, Moscow region, RUSSIA)
Abstract. This lecture is an example how fundamental research in Cosmic Ray Astrophysics and Geophysics can be applied to very important modern practical problem: monitoring by cosmic rays space weather and prediction by using on-line cosmic ray data space phenomena dangerous for satellites electronics and astronauts health in the space, for crew and passengers health on commercial jets in atmosphere, and in some rare cases for technology and people on the ground.

It is well known that in periods of great FEP (Flare Energetic Particle), fluxes can be so big that memory of computers and other electronics in space may be destroyed, satellites and spacecrafts became dead (each year insurance companies paid more than 500,000,000 dollars for these failures; if will be event as February 23, 1956 will be destroyed about all satellites in 1-2 hours, the price of this will be more than 10-20 Billion dollars, total destroying satellite communications and a lot of other problems). In these periods is necessary to switch off some part of electronics for short time to protect computer memories. These periods are also dangerous for astronauts on space-ships, and passengers and crew in commercial jets (especially during S5 radiation storms). The problem is how to forecast exactly these dangerous phenomena. We show that exact forecast can be made by using high-energy particles (about 5-10 GeV/nucleon and higher) which transportation from the Sun is characterized by much bigger diffusion coefficient than for small and middle energy particles. Therefore high energy particles came from the Sun much more early (8-20 minutes after acceleration and escaping into solar wind) than main part of smaller energy particles caused dangerous situation for electronics and people health (about 30-60 minutes later).

We describe here principles and experience of automatically working programs "FEP-Search-1 min", "FEP-Search-2 min","FEP-Search-5 min", developed and checked in the Emilio Segre' Observatory of Israel Cosmic Ray Center (2025 m above sea level, cut-off rigidity 10.8 GV). The second step is automatically determination of flare energetic particle spectrum, and then automatically determination of diffusion coefficient in the interplanetary space, time of ejection and energy spectrum of FEP in source; forecasting of expected FEP flux and radiation hazard for space-probes in space, satellites in the magnetosphere, jets and various objects in the atmosphere and on the ground.

We will describe also the theory and experience of high energy cosmic ray data using for forecasting of major geomagnetic storms accompanied by Forbush-effects (what influenced very much on communications, working of navigation systems, satellites and high-level technology systems in space and, in the atmosphere, and on the ground).

The lecture consists from 7 parts:

1. Introduction

2. Satellite malfunctions and space weather.

3. Data from the past and classification of space weather dangerous phenomena (NOAA classification and its modernization)

4. On-line search of the start of great Flare Energetic Particle (FEP) events, automatically formation of Alerts, estimation of probability of false alerts and probability of missing alerts (realized in Israel Cosmic Ray Center and Emilio Segre’ Observatory).

5. On-line determination of flare energetic particle spectrum by the method of coupling functions.

6. On-line determination of diffusion coefficient in the interplanetary space, time of ejection and energy spectrum of FEP in source.

7. On-line forecasting of expected FEP flux and radiation hazard for space-probes in space, satellites in the magnetosphere, jets and various objects in the atmosphere, and on the ground in dependence of cut-off rigidity.

8. Cosmic ray using for forecasting of major geomagnetic storms accompanied by Forbush-effects.
1. Introduction

Cosmic rays (CR) is one of important objects of space weather because namely CR of galactic and solar origin determined radiation storms and radiation hazard for people and technology, computer and memory upsets and failures, solar cell damage, radio wave propagation disturbances, failures in communication and navigation systems. Beside this CR can be used as effective instrument for space weather monitoring and forecasting dangerous phenomena. In Fig. 1 are shown space weather effects on satellites, communication, navigation systems and others.



Fig. 1. Space weather effects (from Bell Laboratories web-site in Internet).

In Fig. 2 are shown information from insurance companies on the premiums what they paid for satellite losses and failures (at least about half was caused by space weather effects).



Fig. 2. Market premiums of insurance companies for satellite losses and failures in 1990-2000.
From Fig. 2 can be seen that the annual premiums are many hundred millions dollars. Let us note that there are not excluded very rarely, but very dangerous space phenomena (as ,for example, it was solar event at February 23, 1956), when can be destroyed about all satellites in 1-2 hours, the price of this will be more than 10-20 Billion dollars, total destroying satellite communications and a lot of other problems).
2. Satellite Malfunctions and Space Weather.
Let me present our preliminary results of a Project INTAS -0810, which is aimed to improve the methods of safeguarding satellites in the Earth magnetosphere from the negative effects of space environment (Belov et al., 2002). Satellites usually spend several years in space, so they are exposed to the short and long-term effects of space weather. There is a body of evidence on the existence of spacecraft anomalies, which are caused by the space environment. However till now thorough statistical analysis of spacecraft anomalies in dependence of different parameters of space weather have not been done. For the purposes of such analysis malfunction data on “Kosmos” satellite series (circular orbit at altitude about 800 km, 74º inclination) in the period 1971-1997 were combined in one database together with similar information on other spacecrafts (let us note that data on USSR and Russian spacecrafts are introduced into open scientific usage for the first time). Since these data refer to a unique series of satellites of the same type, the classification and the further comparison of anomalies with space environment parameters may be thought as more reliable. This database contains, beyond the malfunctions information, various characteristics of space weather: geomagnetic activity indices (Ap, AE and Dst), fluxes and fluences of electrons and protons at different energy intervals, high energy cosmic ray variations and other solar, interplanetary and solar wind data. Some results are shown in Fig. 2.1-2.7.

Fig. 2.1. A big number of satellite malfunctions in October 1989.
Fig. 2.1 shows that during October, 17-25 we had 69 satellite malfunctions as whole, but the only 2 of them were on low altitudes (both on “Kosmos” satellites). In this period it was several proton enhancements, 3 GLEs (19, 22 and 24 October), great Forbush-effects, strong geomagnetic storms, including severe (Kp=8+) storm on 20-21 October.




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