About using MSSP-1 interface This interface allows users to create one, or a series of, spectral plots of energetic proton or alpha particle fluxes from one or more data sources. Users may scan the available data as time series plots to find intervals of special interest by clicking on the desired row of the interface's "Data Source, Plot/List" column. This yields an OMNIWeb-Plus plot/list interface for the selected data set. Users specify for which data set(s) they want to generate spectral plots. Users specify whether to generate spectral plots for protons or alpha particles. (The Voyager/LECP ion fluxes are considered protons for this purpose.) Users specify the time span over which the fluxes to be shown in the first spectral plot will be created. Note that this may be to hourly or daily resolution. Note also that the end hour or day specified will be included in the flux averaging. Data are held at various time resolutions for various data sets. Users may create, on the fly, spectral plots for fluxes at (a) the lower of (a1) hourly resolution or (a2) the resolution of the lowest-resolution data set selected for display, or at (b) any lower time resolution. The averaging used in these flux determinations is discussed below. To create a plot, after having specified which species and data sets, the user specifies a start time and a stop time. For plots spanning integral numbers of whole days, users should use the format YYYYMMDD in their time specification, otherwise they should use YYYYMMDDHH. The horizontal error bars show energy bins, while the vertical error bars show standard deviations in flux averages (see discussion of averaging below). Since we plot spectra on a log-log scale, we fix a minimum flux value for plotting at 1.0E-06. However, computed average values of fluxes (even if<1.0E-6) and their standard deviations are listed via the "Listing of spectral function points ..." option on the plot pages. [In the flux vs. time plots reached with the "Data source, Plot/List" links on this MSSP page, the minimum flux plotted is either 1.E-5 or 1.E-6 according to which data set is involved.] Having created a first plot, a user may generate similar plots for contiguous intervals of the same duration by clicking on the "Previous" or "Next" button of the spectral plot page. Clicking on the "Home" button returns the user to the default version of the interface page. Users may ensure that all plots of a given series of plots have a common Y-axis range by specifying a minimum and maximum flux in the "Y scale range" option near the bottom of the main interface page. Otherwise IDL will fix the scale range for each plot according to the data range on that plot. (Bottom of the range should not be less than 1.0e-6.) The page with the spectral plot offers the option to list digital values associated with the plots, including energy bin minimum and maximum values and geometric means (where spectral points are plotted), the average fluxes and their standard deviations, and the numbers of individual fluxes in the flux averages. The spectral points for each source for each output plot are fitted to a power law, F = A * E ** b, where F and E are flux and energy, and where A and b are the fit parameters. A and b are determined by a linear least squares fit to the relation Log(F) = Log(A) + b * Log(E). The A and b values are also given on the digital output page. Note that users may specify the energy range over which to include data in plots and fits by using the "Enter energy range..." option near the bottom of the interface page. If this option is not specified, the plot will span the minimum to maximum energy bins of any of the data sets selected. The interface page's "Advanced plot selections" allow users control of the appearance of the output spectral plots. Computing the lower resolution fluxes - Ideally, one should determine a long-term flux using the total number of relevant counts over the interval and the total time of counting over the interval. However, since at least some of the data sets we hope to support with this interface provide fluxes and flux uncertainties but not all the counts and observing times for each such flux, we cannot determine longer term fluxes this way. Accordingly, we take simple linear flux averages and their standard deviations to determine longer term fluxes and their uncertainties. Note on plotted vertical error bars To avoid the down legs of vertical error bars frequently reaching to the bottom of the plot on our log scale, we fix the bottom of the vertical error bar at F = Fmin = <F>**2/(<F>+sigma). Thus the error bar goes up from Fmin to Fmax (=<F>+sigma), with <F> half way up the error bar on the log scale. We've used Fmax/<F> = <F>/Fmin. The numeric value of the linearly computed standard deviation, sigma, is given via the "Listing of spectral function points..." option on the plot page. ------------------------------------------------------------------- This interface and its capabilities were developed by Natalia Papitashvili and Joe King as part of the Virtual Energetic Particle Observatory (VEPO) activity, John F. Cooper, Principal Investigator, carried out within NASA/Goddard's Space Physics Data Facility. -------------------------------------------------------------------