Interaction of solar flare X-rays with the atmosphere of Titan

During solar flares an intense flux of X-rays is emitted into space. When it reaches Saturns orbit, it is still strong enough to significantly disturb Titans dense atmosphere. The main effect is to ionize the neutral component of the atmosphere and to increase, therefore, the electron and ion density at altitudes of 400–900 km. Especially near a maximum of the solar cycle, when flare activity is high, the average plasma density can, for long intervals, remain at a level of a few tens of particles per cm3. As a result, the atmospheric photochemistry will be affected, but also an increase of production rate of small haze particles might be expected. Ionized atoms are usually excited ; when they relax to the ground level in the process of resonant fluorescence, Titans albedo at specific wavelengths increases. It is estimated that at Earth orbit the flux of photons emitted from Titan in the 3 KeV argon line during a strong X1-type flare is equal to 1.6×10−20 J m−2 s−1 for 10% Ar abundance in Titans atmosphere.