摘要: Magnetospheric storms and substorms are the main manifestations of what are nowadays known as the “space weather” which has a practical impact on modern technology systems and our activities on Earth. Various spacecraft have been investigating the space environment around the Earth to explore the effects of substorms and storms－the THEMIS (Time History of Events and Macroscale Interactions during Substorms) and the ERG (Exploration of energization and Radiation in Geospace) missions for example. In particular, substorms are disturbances in the Earth's magnetosphere that causes energy to be released from the "tail" of the magnetosphere to the high-latitude ionosphere. The enhancement in electron fluxes during substorms can be a few orders greater than the pre-onset conditions. Since a fierce debate on substorm onset triggering has persisted for a long time, it highlights a pressing need for a better understanding of substorms in developing the space weather research. Two categories of substorm onset initiation models have been proposed－the Near-Earth Neutral Line model and the Current Disruption model. After the launch of the THEMIS quintet, some notable results even reported a new scenario – plasma intrusion to the inner plasma sheet. Thus starting a further exploration of substorms is inevitable. We will put forth a proposal to settle one of the center issues in dispute, the definition of substorm onset, by investigating the auroral streamers.