Question
What is the cause of short-term radio blackouts?
Answer Options
- A) Coronal mass ejections
- B) Sunspots on the solar equator
- C) North-oriented interplanetary magnetic field
- D) Solar flares
Correct Answer: D
Explanation
Short-term radio blackouts are sudden, widespread events that cause a near-total loss of HF radio communication on the sunlit side of the Earth. These events are specifically related to the immediate and intense burst of energy released from the Sun, making the propagation path unusable without warning.
The cause of these short-term radio blackouts is Solar flares. A flare releases a massive burst of X-rays and UV radiation, which travels to Earth at the speed of light. Upon hitting the Earth’s atmosphere, this radiation causes a rapid, intense increase in ionization in the D-layer, leading to a severe and sudden absorption of HF signals, often lasting from minutes to an hour.
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