How Common are X-type Solar Flares?

Background:

X-type solar flares are the most powerful explosions of energy in the solar system!

Main Data Archive -This is the full storm data archive. It includes a continuous Running Day Number in Column 2 so that Excel plots can be made of the entire archive or selected data columns to search for correlations or other phenomenology. Main Storm Archive (Size = 660 kiloBytes).

Approach:

  1. Students will be separated into 5 to 8 groups.
  2. Each group will be assigned one (or in some cases two!) years of the record.
  3. Locate the column in the archive identified as 'Solar Flares'.
  4. Each group of students will tabulate the number of flares recorded in each category of flares: M5, M6, M7, M8, M9, X1, X2, ..... X30. Allow students 15-20 minutes to complete this work.
  5. Students will enter their findings on a master sheet which is designed with one row per year, and 12 columns. The first 10 columns will be used for recording the number of flares of category M5, M6, M7, M8, M9, X1, X2, X3to4, X5to10, X11to30. The 11th column will be used to record the total number of M5 to X30 flares during that year. The 12th column will be used to record the total number of X-class flares detected during that year.
  6. Students will construct a plot whose horizontal axis is the year (1996 to 2003) and whose vertical axis is the number of X-class flares. Plot the total number of X-class flares recorded during each year from the entries in column 12.
  7. On a separate graph, plot the percentage of the total number of X-class flares (column 12) in relation to the total number of M and X-class flares recorded in column 11 by dividing the entry in column 12 by the entry in column 12 and then multiplying by 100%.

Students should then answer the question based on their data. Note that the percentage of X-class flares may not be a constant percentage throughout each year of the sunspot cycle. Students will be able to understand this in terms of the increasing number of M-class flares as the sunspot cycle approaches its maximum during the years 2000-2001.