When the sun is sharp, especially during a solar flare, sensitive X-rays, ultraviolet rays, etc. are exposed. from the sun make the D level of the ionosphere thicker, which enhances the long waves, however, the short waves reflected from the E and F levels have attenuated due to the strong absorption by the D level. Time later , the energetic particles produced by the solar flare arrive on the Earth, they move towards the geomagnetic poles because of the Earth's magnetic field. Therefore, they influence the ionosphere and cause interference in radar and radio communications at high latitudes.