Sudden ionosphere disturbance (SID) often coincides after a strong solar eruption and produces strong ionization down to which atmospheric layer, potentially causing absorption?

Sudden ionosphere disturbance (SID) often coincides after a strong solar eruption and produces strong ionization down to which atmospheric layer, potentially causing absorption?

• A. D layer
• B. E layer
• C. F layer
• D. G layer

Answer: (B)

When a strong solar eruption occurs, X-rays rapidly ionize the lower ionosphere. This causes a quick surge in electron density down to the D region, roughly 60–90 km above the surface. The D layer has a high collision frequency between electrons and neutral particles, so the increased electrons readily absorb HF radio waves, leading to the absorption that SID can cause. The E layer is higher and doesn’t produce the same absorption effect, while the F layer is farther up and mainly affects refraction rather than absorption. So the layer responsible for the SID-related absorption is the D layer.

When a strong solar eruption occurs, X-rays rapidly ionize the lower ionosphere. This causes a quick surge in electron density down to the D region, roughly 60–90 km above the surface. The D layer has a high collision frequency between electrons and neutral particles, so the increased electrons readily absorb HF radio waves, leading to the absorption that SID can cause. The E layer is higher and doesn’t produce the same absorption effect, while the F layer is farther up and mainly affects refraction rather than absorption. So the layer responsible for the SID-related absorption is the D layer.