The existence of (p,q)-extended Rosa sequences

A (p,q)-extended Rosa sequence is a sequence of length 2n+2 containing each of the symbols 0,1,…,n exactly twice, and such that two occurrences of the integer j>0 are separated by exactly j-1 symbols. We prove that, with two exceptions, the conditions necessary for the existence of a (p,q)-extended Rosa sequence with prescribed positions of the symbols 0 are sufficient. We also extend the result to λ-fold (p,q)-extended Rosa sequences; i.e., the sequences where every pair of numbers is repeated exactly λ times.     

Radio and EUV signatures of a solar flare-CME event on November 28, 1998

Using the observational data of the solar radio spectrometer with a broad bandwidth of the Chinese National Astronomical Observatories (CNAO), the Nobeyama Radio Heliograph (NoRH) and Polarimeters (NoRP), YOHKOH and SOHO satellites, it is found that there are two characteristics in an X3.3 flare event associated with coronal mass ejection (CME). (i) X-ray and EUV loop interaction and evolution appeared evidently in corona, followed by the formation of a twisted loop structure, which is consistent with the theoretical calculations of Amari et al. (1999a,b) for the origin of flare-CME events. (ii) The slow frequency drift was shown in the radio observations, corresponding to the relevant movement of the radio source observed by NoRH, at a speed of several tens kilometers per second, which may be associated with the speed of the shock waves resulting from the CME.     

Radio and EUV signatures of a solar flare-CME event on November 28, 1998

Using the observational data of the solar radio spectrometer with a broad bandwidth of the Chinese National Astronomical Observatories (CNAO), the Nobeyama Radio Heliograph (NoRH) and Polarimeters (NoRP), YOHKOH and SOHO satellites, it is found that there are two characteristics in an X3.3 flare event associated with coronal mass ejection (CME). (ⅰ) X-ray and EUV loop interaction and evolution appeared evidently in corona, followed by the formation of a twisted loop structure, which is consistent with the theoretical calculations of Amari et al. (1999a,b) for the origin of flare-CME events. (ⅱ) The slow frequency drift was shown in the radio observations, corresponding to the relevant movement of the radio source observed by NoRH, at a speed of several tens kilometers per second, which may be associated with the speed of the shock waves resulting from the CME.