Question
Answer the following question:
The earth’s field departs from its dipole shape substantially at large distances (greater than about 30,000 km). What agencies may be responsible for this distortion?
Solution
At large distance, the field gets modified due to the field of ions in motion (in the earth's ionosphere). The field of these ions, in turn, is sensitive to extraterrestrial disturbances such as the solar wind. Hence, there is distortion in the earth's field.