C1 Introduction file for Corona Calculation


There are several files as follows:

            C1coronaIntroduction.doc (this file)








             corona1-54.xlsm          (all gases, one-click each gas)

 Latest development is a modification into a macro with one-entry, one-click for each element; covers all element with atomic numbers 1-54.

Procedure: 1. Download corona1-54.xlsm . 2. Open the macro 

3. In cell B4 type in the atomic number of the element you choose. (one entry) 4. Type in the min and max temperature in the range of temp you desire.

5. "Ctrl+a" to run (one click)


The Introduction.doc file which is this file you have just opened describes:


Corona model calculation for

1  Ionization Fractions, denoted by a’s

2. Effective charge of ions, denoted by Zeff  and

3. Specific Heat Ratio, denoted by g.


Uses a Corona Model (such as discussed by H Griem in Plasma Spectroscopy 6-11) as a better approximation than the Saha Equations for PF operations.


To run the programme:

 Click on the programme file C2coronaNeon.xls.

The Active Sheet opens.

Type in the starting temperature and the maximum temperature to specify the range you want. To illustrate, change the T Max value to a small one such as 10,000,000.

Place the cursor in any unused cell.  Operate ‘Ctrl’+’A’.


The code will calculate the values of a’s within the range you have specified, in this case, 10,000 to 10,000,000K.


Results are displayed in columns, T in K, T in eV, log T

Then follow the columns with the a’s 0-10 for Neon,

Followed by a column for Zeff, a repeat column for TeV

And a separated column for the specific heat ratio g.


The graphs for Zeff and g are also displayed.


The gas has been set for Neon.


To make changes to the code:


Click on Tools

Click on Macro

Click on Macros

Click on’Step Into’

 The code will be displayed.


Some notes on the code:

Dimension has been set as 54 to accommodate gases up to Xenon.

The Ionization Energies (in eV,  each referenced to Ground State of the respective ion) of Neon are entered as I(1)……I(10). M is set as 10.


If you wish to change to another gas, say Argon; you will need to set M=18

And key in the values of I(1) to I(18) using the correct values for argon.


Also go to the statements “For L= 0 to 9” and change to “For L=0-17”

And go to statements “For L=1 to 10” and change to “For L=1 to 18”

And go to statement “For L=0 to 10” and change to “For L=0 to 18”


After the changes, exit from code by clicking on red square “X” in upper right hand corner. Click OK to message “Command will stop the debugger”


The Active Sheet will appear and you are ready to compute with the revised code.


Notes on the Graphs


The graphs are formatted on the Active Sheet. The format may need to be adjusted when a new gas is computed. The formatting uses regular EXCEL techniques.


Also a third file C3 for Xenon calculations

And a fourth file for C4coronaNitrogen.xls