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Select the Shot and Time of Analysis

This section allows you to change the shot number, the SNAP analysis time, and smoothing time for time-averaged data. The smoothing time that you specify is the half-width, i.e., data vs time is averaged over the interval Whenever data is averaged, the percentage error in the averaging is shown in the menus.

After entering the shot, SNAPIN displays the current comments from the SNAP.DAT file. It also shows a table of diagnostics and times of interest for profile waveforms that are available for that shot.

   <0=MO> Option for SHOT 58505 @ 3.400 s? <Sh>:  ,

   <1> New shot? <58505>:    ,
   Old Comments -----------------------------------------------------
   repeat of try 1 but use VB for Zeff.  Earlier cases bombed
   But try 58505/01 indicated that the zeff from vb would be 3.88.
   This case may bomb due to negative thermal ion density

       TS  3.406
       TV  _____
       YS  1)_____  2)_____  3)_____  4)_____  5)_____
       YM  1)1.000  2)2.500  3)3.400  4)3.400  5)5.000
       FM  1)1.000  2)2.500  3)3.400  4)3.400  5)5.000
       BRV 1)1.018  2)2.490  3)3.410  4)3.410  5)5.020
       BRT 1)1.018  2)2.490  3)3.410  4)3.410  5)5.020

   \* Options are:

    1) Time of SNAP analysis ......... < 3.400>
    2) TOi .................. 1)1.000  2)2.500  **3)3.400  4)3.400  5)5.000
    3) Dt half-width for smoothing ... < 0.040>
    4) TOKamak  ...................... <TFTR>
You can change the SNAP analysis time by selecting a time of interest with the TOI option followed by an integer indicating the time you want, or by selecting the Time of SNAP analysis option and entering the time. The time-of-interest nearest the SNAP\ time, which is prefixed by **, will be the default for subsequent time-of-interest waveform reads. (Note that selecting a time of interest changes the SNAP analysis time.)

Your responses in this section affect how SNAPIN will function hence-forth.

Only the diagnostic data needed by SNAP for its analysis is forced to be reread if a menu item is labelled invalid. User-defined switch settings do not need to be re-entered. For example, since you typically want to use the same physics assumptions (regarding plasma composition, current profile modeling, etc.) for most snap-tries, SNAPIN does not force you to re-enter these values even if the shot number is changed, i.e., the value from the most recently read SNAP.DAT file or shot-try file is retained.

Whenever SNAPIN fails to read a value (for example, if the file doesn't exist) it will write an error message. If a profile read fails, then that profile is deleted. If a non-profile data read fails, then the value of that parameter is set to zero and ZERO is displayed in the source column of the menu. When SNAPIN\ reads a time-averaged value, like Rmajor, it reads the entire signal vs time and adds an option in that menu to plot that signal.

After visiting the physics sections, select the Comments menu and enter your comments for this shot-try. You must have at least one line of comment.

Finally, select the Write SNAP Input File option and write the new file with the default name of SNAP.DAT. SNAPIN warns you if you are about to write a file with any invalid menu items. This feature tries to prevent you from creating files which have unintentional mixtures of data from different shots.

next up previous contents index
Next: Set the Physics Controls Up: SNAPIN--Preparing the Input to Previous: Read a SNAP Input

Marilee Thompson
Fri Jul 11 15:18:44 EDT 1997