Study On The True Period Of The Sunspot Oscillations Observed By CaII Line

The phenomena of oscillation on the sun are widespread in most parts of the sun.These oscillations may be important tools for detecting the magnetic field structure,plasma density and temperature distribution characteristics of the sunspot.Therefore,it is very important to understand the nature of the oscillation in the active region.These oscillations generally show a certain periodicity,we initially determine the size of the cycle between different oscillation phenomena are related.However,it is not enough to study the relationship between different oscillations only by the oscillation period.Current research shows that the oscillation phenomenon is caused by the change of the local physical quantities passing by a traveling wave in the sun and oscillating.Generally considered the cycle of oscillation performance is the cycle of traveling waves,but this is unscientific.The period of the oscillation period and the traveling wave that causes the oscillation are not necessarily equal.Traveling waves are difficult to observe or even can't observe directly,so it is very difficult to determine the traveling wave period by direct observation.Therefore,we find another way to speculate the period of the traveling wave from the statistical law shown by the sunspot oscillation.The first chapter of this paper introduces the sun's layered structure and the atmospheric and magnetic properties of sunspots.The second chapter introduces the sunspot oscillation classification,that is,3 minutes oscillation and 5 minutes oscillation.The third chapter introduces the types and transitions of some wave theory in the sun.The fourth chapter introduces the waves in sunspots,including possible driving mechanisms and features.Chapter 5 for our work,we use the Hinode telescope observed a series of successive sunspot evolution images on March 4,2014 under the Ca II H(396.85 nm)line.We calculate the oscillation period of sample point is about 149.75 seconds by the Jurkevich method(JK method).A suitable average of the intensity profile is selected as the steady background radiation,then the distribution of the extreme value of the Oscillation in umbra is analyzed by statistical method.The results show that the trough is a normal distribution and the peak is a skewed distribution.The distribution of this extreme value indicates that the three-minute oscillation of the umbra may be caused by the propagation of a traveling wave with a period of about five minutes in Umbra.The variation of the light intensity caused by the traveling wave may be proportional to the square of the displacement of the traveling wave,resulting in a period of light intensity change of half the period of the traveling wave,so a three-minute period is happened in changes of light intensity.