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Ulysses HISCALE Data Analysis Handbook

 

Appendix 2. User's Guide to LAN360

 

A2.1 Description of Inputs

 

The user can control parameters of the plot as listed below:

 

  • Length of plot in hours and minutes. *
  • Minimum flux value and number of decades for time series plot. *
  • Anisotropy maximum scale value and option for linear or log scaling for mapping to the color bar. *
  • Choice of electron, proton, or wart channels (P1-7, E1-4, W1-2) and optional deflect factor for the electrons and foil factor for the ions. Also option to fill in the LEMS120 electrons with LEFS60 values shifted by 180°. *
  • Option to read input from ULA or UAV files.
  • Option to interpolate (linear smooth) between adjacent channels.
  • Option to normalize each panel separately or all together.
  • Option to write an HDF file.
  • Begin and end time to start and end plotting. This can be typed or read from the file time.dat as in LANSPECT and other analysis programs. The time is used to construct a default file name; it can be accepted, or an alternative can be typed in.

 

Energy ranges and geometry factors for the requested channel are read from the IDF.DAT file; the version number of the IDF.DAT is printed on the plot.

The input parameters labeled * above can have default values read from a file (lan360.dat); they may be changed from the keyboard at run time if desired.

 

A2.1.1 Coordinate System

 

The anisotropies are calculated for three orthogonal planes in the S/C coordinate system. This system is defined by +Z pointing to Earth, the Sun being between +Z and +X, and Y completing a right-hand system. This definition of S/C coordinates may cause confusing effects if an event is being analyzed which occurs during a conjunction of the Earth and the Sun (as viewed from Ulysses). At such a time the definition changes the S/C coordinates relative to the absolute coordinates. Z of course still points to the Earth, X will change from pointing (for example) East to now pointing West, and Y will similarly change to point North instead of South, or vice versa. N. B.: the North/South panel labels are valid only in a configuration with the Sun to the right of the Earth as viewed from the spacecraft, as is true in the vicinity of Jupiter. (Out of the ecliptic plane, the geometry will become even more complicated; near the South polar pass, the Z axis will be pointing roughly North!)

 

A2.1.2 Layout for Electron and Proton Plots

 

The top panel of the LAN360 plot depicts the X-Z plane. The idea is to average together the sectors just above and just below the plane of interest. These sectors for the X-Z plane are shown in Figure A2-3. This then gives values of flux in 8 directions (azimuths) around the X-Z plane. After suitable normalization and conversion to a color bar, these values are plotted as a vertical strip at the appropriate time. The "smooth" option invokes linear smoothing between anisotropy values in adjacent directions. No smoothing is done vs. time.

 

Figure A2-3 Diagram showing the 16 sectors that are used to determine the anisotropies for the spacecraft X-Z plane, the detectors from which the measurements are made, and their final location on the LAN360 plot.

 

Figure A2-3

 

A2.1.3 Layout for WART Plots

 

The option to plot WART channels results in a plot that differs from the electron and proton options in that each of the top three panels represents a different species for the same (X-Y) plane. Since LAN does not have 360° coverage for this data, the three panels instead represent different species (see Figure A2-4). The option to normalize panels separately is automatically set when plotting WART channels. Because of poor statistics in the WART channels, using time-averaged data is recommended.

 

Figure A2-4 LAN plot for WART channels in the XY plane for hours 0-24 UT on day 33, 1992 when Ulysses enters the Jovian magnetosphere. All panels are the same (XY) plane. The top panel is the Hydrogen (W1) anisotropy, the middle panel is Helium (W3), and the third panel is the CNO (W5) anisotropy. This plot is made from a LANAVG file of 15-min averages. The time series plot in the bottom panel shows the 15-min average points for W1 (red), W3 (green) and W5 (blue).

 

Figure A2-4 

 

A2.1.4 Time Series Plot

 

The lower panel of the LAN360 output shows a time series of the average flux in the upper panels. Normally the traces will be plotted with the colors red, green and blue, corresponding to the fluxes in the top, center, and bottom anisotropy panels, respectively. The scale is set by two variables, minvalue and ndcad, which are read from the lan360.dat file. For example, minvalue =10 and ndcad =3 will result in a vertical scale from 1. to 4. in the log (i.e., 101 to 104 ). If the flux value goes off scale, it will automatically be wrapped around. To indicate this case, the color is changed to purple.

 

Because the WART plots show three different species, the time series plot may need a wider range than for the electron and proton plots which show the same species in different planes.

 

 

Next: Appendix 2.2 Available Channels

Return to Appendix 2 Main Table of Contents Page

Return to Ulysses HISCALE Data Analysis Handbook Table of Contents

 


Updated 8/8/19, Cameron Crane

QUICK FACTS

Manufacturer: ESA provided the Ulysses spacecraft, NASA provided the power supply, and various others provided its instruments.

Mission End Date: June 30, 2009

Destination: The inner heliosphere of the sun away from the ecliptic plane

Orbit:  Elliptical orbit transversing the polar regions of the sun outside of the ecliptic plane