It is believed Mars suffered a cataclysmic impact event in its early history that damaged the planet's internal "dynamo." Therefore, its magnetosphere was shut down and any residual magnetic field acts as mini-magnetic "umbrellas."
It is thought that these magnetic umbrellas my be the root cause of the thin Martian atmosphere. As the solar wind continually buffets Mars, the magnetic umbrellas get "pinched off," carrying atmospheric gases into space. This might explain why the planet's atmosphere is 100 times thinner than Earth's.
According to Spaceweather.com, there is circumstantial evidence from data collected by the NASA's Mars Global Surveyor (1996-2007) that suggests these magnetic umbrellas also generate their own aurorae when particles from the sun impact the Martian atmosphere.
Like the satellites in orbit around the Earth, the three satellites in orbit around Mars (NASA's Mars Reconnaissance Orbiter and Mars Odyssey, plus the European Mars Express) are vulnerable to damage by the sun's high-energy particles impacting their circuitry.