地球對太陽風暴的反應 高速太陽風與強烈的日冕物質噴射會引發地球磁場與地球上空電流系統的劇烈變化，亦即造成地磁暴 (geomagnetic storms)與磁副暴(magnetic substorm)的發生。 其中磁副暴發生時會於地球兩極區上空產生迷人的極光(aurora)。 宇宙射線與太陽閃焰的強烈輻射則會和地球低層大氣作用，被認為與長期氣候變化有關。

Presentation on theme: "地球對太陽風暴的反應 高速太陽風與強烈的日冕物質噴射會引發地球磁場與地球上空電流系統的劇烈變化，亦即造成地磁暴 (geomagnetic storms)與磁副暴(magnetic substorm)的發生。 其中磁副暴發生時會於地球兩極區上空產生迷人的極光(aurora)。 宇宙射線與太陽閃焰的強烈輻射則會和地球低層大氣作用，被認為與長期氣候變化有關。"— Presentation transcript:

1 地球對太陽風暴的反應 高速太陽風與強烈的日冕物質噴射會引發地球磁場與地球上空電流系統的劇烈變化，亦即造成地磁暴 (geomagnetic storms)與磁副暴(magnetic substorm)的發生。 其中磁副暴發生時會於地球兩極區上空產生迷人的極光(aurora)。 宇宙射線與太陽閃焰的強烈輻射則會和地球低層大氣作用，被認為與長期氣候變化有關。

2 太陽風的帶電粒子進入地球磁層的動態示意圖

3 太陽風的帶電粒子如何進入地球磁層 Solar wind particles are not able to penetrate to the Earth's surface but are forced by the magnetic field to move around the Earth. Particles gain entry through the cusps that are shaped like funnels over the polar regions or they gain entry far downstream from the Earth. The particles that enter downstream travel toward the Earth and are accelerated into the high-latitude ionosphere and produce the auroral oval light shows. Other higher energy particle radiation that could pose a danger to life here on Earth, is forced to drift around the Earth within two large donut-shaped regions called the radiation belts. Invisible magnetic fields are the reason that particle radiation moves in this way.

4 上圖為用於表示磁暴強度的DST指數，此圖為2003年11月的磁暴紀錄，其中曲線大幅陡降處為磁暴的發生。其地磁變化幅度達500nT (nano-Tesla)，是少見的強磁暴事件。

5 極光與磁副暴

6 右圖為POLAR衛星以可見光拍攝的極光橢圓圈(圖上的亮環)，地球左上半球的明亮範圍是太陽光照射所致。
磁副暴發生時才會出現的明曜區域

7 POLAR以可見光拍攝之極光橢圓圈在磁副暴發生時的發展過程

8 人造衛星POLAR以極紫外波段(Ultraviolet)拍攝的極光於磁副暴發生時發展的
過程，依序由左上向右，再由左下向右。

9 人造衛星POLAR以極紫外波段(Ultraviolet)拍攝的極光活動性之動態過程

10 磁副暴發生時POLAR衛星以X射線波段拍攝的南極上空極光之活動性

11 2005/11/20 地磁暴期間，磁副暴發生時極區磁場變化情形，圖中的極光橢圓圈區磁擾動指數分別有 AU, AL, AE=AU-AL, AO=(AU+AL)/2 等四種指數。

12 電離層對地磁暴的反應 The atmosphere's ionization layers make possible long distance radio communication by reflecting the radio waves back to Earth. They also are home to the aurora and the mega-ampere currents that heat the atmosphere at high latitudes during geomagnetically active times. During storms depletions and enhancements of ionization occur depending on the local time and geographical location. Depletions are particularly effective at causing problems with the normal operation of radio communications.

13 The movie is a 24-hour long simulation of the total electron content in a column above the Earth's surface (between 100 and 400 km altitude) during the April 10-11, 1997 ionospheric storm event. This storm occurred in association with a magnetic storm that began in near-Earth space at ~21 UT on April 10 due to the arrival of a coronal mass ejection from the Sun. The storm subsided at around 9 UT on April 11 but the changes to the ionosphere lasted much longer.