Understanding of space weather

The term "space weather" first appeared in the preface of "Observation and Forecast of Solar Activities" by an American space physicist Dr. M.Dryer in the early 1970s. It refers to the conditions or conditions in the solar wind, magnetosphere, ionosphere and thermosphere on the sun that can affect the normal operation and reliability of space-based and ground-based technology systems and endanger human health and life. It studies the most changeable and harmful weather changes in the whole solar-terrestrial space environment, from the surface troposphere to the solar atmosphere, including the basic processes and changing laws of sudden, short-time scale and dynamic sudden time changes of electromagnetic radiation, charged particles, plasma and neutral atmosphere.

Two. The influence of space weather

In our solar system, space weather is mainly influenced by the wind speed and density of solar wind and the interplanetary magnetic field brought by solar plasma. All kinds of physical phenomena are related to space weather, including geomagnetic storms and substorms, current in the Van Allen radiation belt, ionospheric disturbance and flicker, aurora and current induced by changes in the magnetic field on the earth's surface, etc. Coronal mass ejections and related shock waves will compress the magnetosphere and cause geomagnetic storms. Solar high-energy particles, coronal mass ejections or solar flares will destroy the electronic equipment of spacecraft and threaten the lives of astronauts. Are important driving forces of space weather.

Space weather disasters mainly involve the harm of high-energy charged particles to spacecraft, the serious influence of solar explosion on navigation, communication and positioning, the damage of rapid change of geomagnetic field (magnetic storm) to power transmission system and underground pipeline, and the influence of high-level atmospheric density on the orbital life of spacecraft. These disasters will cause the collapse of satellite operation, communication, navigation and power station transmission network, resulting in social and economic losses. The change of space weather directly affects the development of human science and technology represented by space technology and the high-tech on which social life is increasingly dependent.

Space weather also has a great influence on war. High-energy charged particles in the universe constantly bombard the surface of spacecraft, which will cause radiation damage to spacecraft. Particles with higher energy can pass through electronic equipment, changing the data bits in the electronic signal string, causing the instrument to issue chaotic instructions or provide wrong data. When disastrous weather occurs in space, radio communication and radar signal transmission will be affected, and satellite microwave communication will also reduce the communication quality due to ionospheric disturbance. Ionospheric scintillation will lead to GPS satellite navigation and positioning errors as high as tens to hundreds of meters, and even signal interruption.

Three. Significance of studying space weather

Space weather science was born to adapt to the development of human high technology. Its research object is the occurrence, development and change laws of space weather and how to use these laws to forecast space weather. At the same time, space weather science also studies various space weather effects and methods to avoid and mitigate space weather disasters.

Space weather science should "escort" human high-tech activities, and its ultimate goal is to provide space weather services and reduce or avoid the loss and harm of space disasters. Space weather services include: (1) providing space weather products-conventional products: observation data, models, environmental specifications and effect analysis; Special products (products specially processed according to users' specific needs): forecast products, alarms, on-site reports and forecasts. (2) Effect diagnosis and analysis-identify whether the system abnormality or fault is caused by space weather factors or other engineering design, mechanical failure or software error. (3) Suggest protective measures or improve engineering design. (4) Adjust the operating procedures of ground and space technology systems and take emergency measures.