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How do Magnetic Storms Form?: 

How do Magnetic Storms Form? All magnetic fields have a direction. The solar wind’s field can point in all sorts of directions: towards Earth, away from Earth, towards the north, towards the south, and even towards the east and west. The actual direction of the field when a mass ejection comes crashing into Earth’s magnetosphere is very important. If it’s directed southward, we have found that disturbances in the solar wind, like CMEs, can penetrate Earth’s protective shield and cause magnetic storms. If the solar wind’s magnetic field has some other direction, like northward, then conditions are mild. The direction of the field acts like an electric switch: northward the switch is off; southward it is turned on.

Space Weather: Early Warnings (1): 

Space Weather: Early Warnings (1) Like meteorologists who check temperatures, winds, and pres sure to predict the weather on Earth, scientists monitor the Sun and our space environment to forecast the weather in space. Using spacecrafts like SOHO, Earth-based telescopes, and old-fashioned hand sketches of the Sun, scientists search the surface of the Sun for signs of flares and CMEs. They monitor the solar wind as it blows toward Earth to see if it is carrying foul weather, and they measure the energy flowing into Earth’s upper atmosphere and the distortion of magnetic fields near the ground. From these bits of information, NOAA’s Space Environment Center forecasts whether our space weather will be mild or wild.

Space Weather: Early Warnings (2): 

Space Weather: Early Warnings (2) Utilizing a fleet of spacecraft, scientists in dozens of countries observe the Sun, the solar wind, the near-Earth space environment, as well as the aurora. Ground-based telescopes, radar and supercomputers are used alongside these spacecraft to provide a picture of current and future space weather conditions. We are learning what it means to truly live within the atmosphere of the Sun.

Space weather forecast (1): 

Space weather forecast (1) Space weather forecasts and alerts are issued by NOAA's Space Environment Center (SEC), located in Boulder, Colorado. SEC receives space weather data from many different satellites and ground-based stations around the world. Forecasters track Sunspots, map coronal holes and provide a detailed description of all active regions visible on the solar disk.

Space weather forecast (2): 

Space weather forecast (2) The face of the turbulent Sun, as seen here in Hydrogen-alpha wavelengths, is far more violent than most people suppose. Hydrogen-alpha is an absorption line of neutral hydrogen in the red part of the visible spectrum. It is used to characterize solar flares, filaments, prominences, and the fine structure of active regions.

Space weather forecast (3): 

Space weather forecast (3) Sunspot Groups, like those seen as dark areas in visible-light images of the Sun, are also responsible for X-ray emissions. These are active regions where hot, dense plasmas are energized. They are also associated with regions of oppositely directed magnetic fields which can erupt as a solar flare and coronal mass ejection.

Space weather forecast (4): 

Space weather forecast (4) Forecasters in the SEC monitor the near-Earth space environment. Solar flares produce vast amounts of X-rays and energetic protons which can be detected by NOAA satellites orbiting at geosynchronous altitudes and around the poles. Energetic particles from the Sun and energized plasma in Earth's radiation belt environment can cause damage to satellites.

SEC Today’s Forecast: 

SEC Today’s Forecast Solar Activity

Slide11: 

Solar Wind Activity

Slide12: 

Auroral Activity

The Wang-Sheeley Model : 

The Wang-Sheeley Model The Wang-Sheeley Model predicts the background solar wind speed and the interplanetary magnetic field (IMF) polarity at earth, two important parameters required for predicting geomagnetic activity.

Solar Wind Modeling: 

Solar Wind Modeling Kinematic Solar Wind Model (HAF) The HAF model is a "modified kinematic" model. "Kinematic" in that the model kinetically projects the flow of the solar wind from inhomogeneous sources near the sun out into interplanetary space. NOAA/USAF STOA and ISPM Models The STOA and ISPM models have the same purpose to predict whether a solar event will cause an interplanetary shock that will reach Earth and, if so, the time of arrival and strength of the shock.

Slide16: 

HAF model 模擬 1999年10月17日行星際磁場結構的演化 HAF model

NOAA/USAF STOA and ISPM models: 

NOAA/USAF STOA and ISPM models The Shock Time of Arrival (STOA) model and the Interplanetary Shock Propagation Model (ISPM) have been developed for the purpose of predicting the time of arrival and strength of solar-initiated interplanetary shocks. The STOA model is based on similarity theory of blast waves, modified by the piston-driving concept, that emanate from point explosions. The ISPM is based on a 2.5 D MHD parametric study of numerically simulated shocks.

tsyganenko magnetospheric model: 

tsyganenko magnetospheric model 隨地磁軸的指向改變

Slide19: 

隨穩定行星際南向磁場的變化

Slide20: 

隨動態行星際磁場與太陽風變動的磁層 --- 磁暴與磁副暴

MHD simulation: 

MHD simulation