Spectral Analysis of the Flare of 1998 November 11 based on the Multi-cloud Model

We have obtained 2D spectra of Ha and CaII λ8542A for the flare of 1998 November 11, and derived its 2D velocity field and integrated intensity field. The velocity distribution shows that the red-shift and blue-shift velocities lie respectively in the northern and southern parts of the flare and that the maximum velocity seems to be located in two footpoints of the flare loop system. The integrated intensity distribution shows that the CaIIλ8542A line is formed at a lower height than the Ha line, we used 'multi-cloud model' (MCM) to obtain four parameters for the two lines (Doppler width, △λD, Doppler shift, △λ0, line source function, S, and optical depth at the line center, TO). We also estimated the column number densities of hydrogen at the second level, N2, and of the ionized calcium at the third level, N3, as well as the kinetic temperature, Tc. The wide Hα profile at the loop top may be explained by an overlapping of two or more elementary profiles. It is shown that the uncertainty in calibration does not affect the derived Doppler shift and line broadening, only the source function and optical depth.

Long-term Evolution of Solar Activity and Prediction of the Following Solar Cycles

Solar activities have a great impact on modern high-tech systems,such as human aerospace activities,satellite communication and navigation,deep space exploration,and related scientific research.Therefore,studying the long-term evolution trend of solar activity and accurately predicting the future solar cycles are highly anticipated.Based on the wavelet transform and empirical function fitting of the longest recorded data of the annual average relative sunspot number(ASN)series of 323 yr to date,this work decisively verifies the existence of the solar century cycles and confirms that its length is about 104.0 yr,and the magnitude has a slightly increasing trend on the timescale of several hundred years.Based on this long-term evolutionary trend,we predict solar cycles 25 and26 by using phase similar prediction methods.As for solar cycle 25,its maximum ASN will be about146.7±33.40,obviously stronger than solar cycle 24.The peak year will occur approximately in 2024,and the period will be about 11±1 yr.As for solar cycle 26,it will start around 2030,and reach its maximum between2035 and 2036,with maximum ASN of about 133.0±3.200,and period of about 10 yr.