This tool plots the pitch angle distribution of one or more particle channels.
The pitch angle points are shown for a small time width, which can be dragged across a larger time
window. Think of this time width as a moving window over a larger set of data. The bounds of the
larger time window are determined by the time bounds of the data on the summary plot - either from
the sliding red bars, or from the manually entered time range.
Just below the plot panel is a slider and a set of buttons. You can use the slider to drag the
sliding time window through time, effectively creating a \"movie\" of the pitch angle distribution.
The buttons below the slider are intended to be similar to the buttons you might find on a VCR or CD
player. The meaning of each button is (in the order they appear, from left to right):
reset to the beginning, stop, play, one step back, one step forward, continuous play.
Below the slider and slider controls are buttons which let you 1) save a Postscript plot of data, or 2) get the ASCII values for the data currently displayed. The ASCII data is displayed initially as a table, and the table lets you save the data to a space delimited ASCII file.
The \"Settings\" menu has an item called \"Plot Settings...\" which opens the plot settings window. This window gives you control over how the data in the plot is displayed. The pitch angle points are shown for data in a time window of a certain width, and the first item in the plot settings window lets you change this time width. You will have to click on OK or Apply in order for your new time setting to take effect.
The plot settings window also lets you chosse between two fundamental modes of displaying pitch angle points. The default mode is to show each pitch angle point individually, but you can also choose to have the points grouped into angle bins or arbitrary width. Viewing each point lets you see and understand better the shape of the binned distribution. The plot is initially shown in a mode where each sliding time window is normalized with respect to the maximum flux in that time window. However, you can fix the maximum (i.e., normalizing) flux to any value you want. Just check the box labeled \"use fixed maximum flux value of\", and put the desired maximum flux in the adjacent text box. You will have to ckick on the \"Update Plot\" button to activate your changes. Note that if there are flux values higher than your maximum, they will be shown as filled diamonds at the top of the pitch angle plot.
The remaining settings let you control the appearance of the plot. You can show symbols at each pitch angle point; you can connect the pitch angle points with lines, or you can do both, or even neither. The slider sensitivity can be controlled as well. The sensitivity number in the pulldown menu represents the number of steps (or clicks, or movements of the slider) needed to move the sliding window one time width's worth of time. For example, suppose you set the time width to 30 seconds. With a slider sensitivity of 1, each slider position represents one 30 seconds window. With a sensitivity of 50, it takes 50 clicks (or 50 play steps if you have the slider moving on its own using the VCR-like play button) for the sliding window to move by thirty seconds, thereby slowing down the \"movie\", or giving you finer control over which exact time interval is shown in the plot panel.
This display tool has the capability of combining multiple channels into one pitch angle plot. This is helpful when there are several detectors (or detector heads) with fixed fields of view and you want to be able to combine the pitch angle information from all of them. To combine more than one channel, you simply select more than one channel name. To select more than one channel, hold down the CONTROL key while pressing the mouse button over the channel you wish to add to the list. For example, suppose you wanted to combine 2 channels with the labels CHNL-A and CHNL-B. First select CHNL-A name in the list of channels with a regular mouse click. Scroll the channel window until you can see CHNL-B, and then CONTROL-click on this channel name to combine it with the already selected CHNL-A item. There are several important points to note about combining multiple channels.
First, combined channels should only be viewed using the 'fixed angled bins' mode. Also, the bin width should be chosen carefully according to the actual angular width of the detectors being combined. Finally, it is up to the user to combine channels that make sense. For example, combined pitch angle information should only be viewed for channels with very similar energy ranges.
As a final note: The time resolution of the particle measurements is usually different from the time resolution of the particle measurements. Linear interpolation is used to get the B field measurements at the time of the particle flux measurements.