But major geomagnetic storms such as the Bastille Day event are much rarer.Although they can occur anytime during the 11-year solar cycle, they are most frequent in the solar maximum period.

• 但是像巴士底日这种大型磁暴就少多了，虽然它们随时都有可能发生，但最频繁的发生期间还是在太阳磁场活动的高峰期。