READ ME

Dear Friends:

Thank you for using FLYCHK. This is a brief introduction on how to use the FLYCHK website at NIST using as an example the calculation of steady-state charge state distributions. You may find more complex examples including time-dependent cases at EXAMPLES.

We explain step by step two ways to enter input parameters and how to view the results. Currently, the graphical outputs include the mean charge state <Z>, charge state and ion level population distributions. We hope to implement the capability to produce spectra from the calculations in the near future.

We appreciate your interest and hope FLYCHK can help you design experiments and analyze spectroscopic data. Please do not hesitate to give us feed back on the website interface and/or FLYCHK itself.

Sincerely,

Hyun-Kyung Chung

Yuri Ralchenko

Richard W. Lee

Example: Steady-state charge state distributions of aluminum

It is common to require the average charge <Z> and charge state distribution for a plasma at a given set of electron temperatures and densities. We can, in the most straightforward of cases, obtain results with the input of only three types of parameters: 1) the atomic number of the element of interest 2) a specified temperature grid, and 3) a specified electron density grid.

We assume the element is Al, and we want data for the range of temperatures [50, 100, 150, 200, 250, 300] and the range of electron densities [10²⁰, 10²¹, 10²², 10²³, 10²⁴].

The three input parameters for this case would be:
1) Nuclear charge = 13
2) T_e [eV]	min: 50	max: 300	increment T_e: 50
3) N_e [cm^-3]	min:10²⁰	max: 10²⁴	increment N_e: 10

We now discuss how to run this case, which is achieved by supplying the information into a window which can be seen at the right - click the picture for an enlarged view.

First, in the top panel, you should "title" the case you are about to run with a name that usefully identifies it and check the "Diagnostic output" to provide you with information on the run.

Second, enter the Nuclear charge. Next, enter the manner in which the data will be initialized, i.e., the Initial Condition used to perform the first calculation, followed by the way the calculations will proceed. Here we want the steady-state solution so we choose Steady-State for the Initial Condition and for the System Evolution.

Now to indicate that you want the calculations to be performed on grid of temperature, density points select, on the left hand side, Grid input section.

Click to run the case. Note that at any time during the input you can click for more information on keywords.

Click image for enlarged view

steady-state grid input

While the program is running cases one may press to discontinue the run. After the the run is complete at the bottom of the window a link to the Current results will appear. See the panel below. ***HK wthere is no panel below?***

Another way to run FLYCHK - useful for repetitive runs - is to use the Runfile option. This is done by choosing the Runfile Input on the left hand side of the window. You will upload a text file, which we call the Runfile, that contains all the information necessary for the run. This is described below.

Please note that if more than one (1) file is required for the run then a single a tar file or a zipped file needs be uploaded.

Runfile input : Write and upload the text file (shown in the left column)

  z 13
  initial ss
  evolve ss
  history grid ne
  ne 1e20 1e24 10.
  te 50. 300. 50.
  end

A runfile is constructed with keywords: z, initial, evolve, ss, history, grid, ne, te, end

Please refer either to the manual for a detailed description or click the help window next to the keywords on the grid input page

By clicking on the Current results one may: A) create a plot of the mean ion charge, <Z>, and/or B) create a plot of the charge state distributions, and/or C) view the result files.

To Plot <Z>

(1) First, select the Mean Ion Charge on the top left tab in the PLOTS section and, on the right tab, you can select either Electron Temperature or Electron Density. For the example shown we select Electron Temperature. Next click on .

(2) The next window appears and as Temperature was selected as the x-axis one must select, using the check boxes, which N_e cases to plot as a function of T_e.

One may also give specific ranges for x and y axes, as well as choosing the option to use logarithmic scales. With these things done click on .

(3) Once the is clicked a graph in PDF format is displayed. Depending on your computer, the PDF file can open in the same browser window (PC) or will be downloaded (Mac). The plot shows <Z> for each N_e case chosen, together with information on the run in the lower right hand part of the window.

To Plot Ionization distributions

(1) Select

to the right of Ionization Distribution

(2) The next window appears and one must select, using the check boxes, the (T_e, N_e) cases to plot as a function of ionization state. Here we strongly suggest that one select a single T_e for a range of N_e.

One may also give specific ranges for x and y axes, as well as choosing the option to use logarithmic scales. With these things done click on .

screenshot 2 for plotting ionization ditributions

(3) Plot shows 6 cases of ( T_e, N_e )

To View Current Output Files

1) On the Left hand side under Results select Current

and a window with the list of input and output files will appear:

2) One may look at <Z> data by selecting the Mean Ion Charge file. This file contains the case #, T_e, N_e and <Z> along with power loss rates - separated into bound-bound, bound-free, free-free, and total - in units of [ergs/s/atom]

3) One may look at the charge state distribution by selecting the Ion Stage Distributions file. This file lists the case #, T_e, N_e and the ionization fraction for each charge state. Note that charge state 0 refers to the fraction of the neutral atom.

4) If one wants to download all data files, please select the link to the zipped files at the bottom of the window. For spectral calculations, which will be implemented in the future, the Main Output File is required.

To View Previous Output Files

On the left hand side under Results one may view their runs for the last 14 days by selecting Previous. This is one reason it is useful to give a title to characterize the run.

As a final note we point out that FLYCHK can compute <Z> for more complicated conditions. That is, one can have radiation-field driven plasmas, two Maxwellian temperature plasmas, plasmas with arbitrary electron distributions including an electron beam, optically thick plasmas, plasmas with other species and time-dependent plasmas. Please refer to the EXAMPLE section where you will find runfiles - along with all other files required for a particular example. These files can be uploaded using the Runfile Input option .