Analyses - Intensity Spread Function

Navigation: Analyses Commands > Intensity Spread Function

Intensity Spread Function

Page Contents

Description

Description

The Intensity Spread Function calculates flux/steradian (intensity) for rays filtered by a user-selected analysis surface. Incoherent, coherent, and coherent polarized rays will be incoherently summed together if filtered by the analysis plane. The intensity distribution is calculated by binning the filtered rays by solid angle as defined by the analysis surface. Note that all binning is done in direction cosine space, not in angle space. During the analysis, results are printed the the FRED output window.

NOTE: The intensity calculation is valid only for incoherent sources.

Intensity has units of power/steradian (W/sr, in SI units). Using the following diagram, we define Intensity mathematically as:

where F is the power, W is the solid angle and r is the distance between the source and the area dA.

Navigation

This command can be accessed in the following ways:

•Menu > Analyses > Intensity Spread Function

•Ctrl + F12

•Toolbar button:

Controls

Control	Inputs / Description	Defaults
Use This Analysis Surface
Use This Analysis Surface	Lists the analysis surface used to filter the rays.	Selected analysis surface
List of Available Analysis Surfaces
List of Available Analysis Surfaces	Lists the available analysis planes for use as the ray filter.	Valid analysis surfaces.
Pre-Analysis Ray Operations
Delete old rays and recreate all active sources	If checked, existing rays are deleted, and new rays are created before the analysis proceeds.	Unchecked if rays exist. Checked if no rays exist.
Raytrace all active rays	If checked, any existing rays are raytraced before the analysis is performed.	Unchecked if rays exist. Checked if no rays exist.
Plot the rays as they are being raytraced	If checked the rays will be drawn to the 3D view when traced.	Unchecked

OK	Perform analysis and close dialog box.
Cancel	Discard analysis and close dialog box.
Help	Access this Help page.

Application Notes

Chart crosshairs

Chart crosshairs are available by holding the left mouse button down inside the plot. The intensity at the selected chart position is reported at the bottom of the chart in both xy-angles and in polar-azimuthal angles (relative to the local analysis plane X axis).

Right mouse clicking in the chart view brings up a list menu that contains the item "Move Profile Lines To". The options on the sub-menu list can be used to precisely and rapidly locate the crosshairs at common positions of interest.