Data Set Summary ================ Data Set ID: ULY-J-URAP-4-SUMM-WFA-PEAK-B-10MIN-V1.0 Instrument: URAP Waveform Analyzer (WFA) Instrument P.I.: Robert J. MacDowall Data Supplier: Roger Hess Data sampling rate: 10 minutes Data Set Start time: 1991-11-26T00:00:00.000Z Data Set Stop time: 1992-06-07T23:50:00.000Z Naming convention ----------------- Data files in this data set are named according to the convention: Tyyddd.TAB where yy = the last two digits of the year ('92' for 1992) ddd = the day of the year covered by the file Record format ------------- These files can be read according to the FORTRAN format statement: '(a24,2x,3i1,22(1x,1pe9.2))' where 'a24' is the time stamp in PDS format: yyyy-mm-ddThh:mm:ss.sssZ. The individual elements of the time field can be read according to the statement: '(i4,4(1x,i2),1x,f6.3,1x)' year, month, day, hour, minute, seconds. thus a record may be alternatively be read according to the format: '(i4,4(1x,i2),1x,f6.3,3x,3i1,22(1x,1pe9.2))' Data column descriptions ------------------------ time a24 spacecraft event time antenna i1 used for low band (0.22 to 5.33 Hz). The high band (9.8 Hz and above) is always By. 1: By 2: Bz 3: Antenna switched during the averaging interval. 4: Antenna unknown. pfrmode i1 Indicates the scan mode of the PFR instrument. 1: Fast scan mode. 2: Slow scan mode. 3: Fixed-frequency mode. 4: The mode switched during the averaging interval. 5: The mode could not be determined. bps i1 Telemetry bit rate: 1: 128 bps. 2: 256 bps. 3: 512 bps. 4: 1024 bps. 5: Bit rate changed during averaging period. 6: Bit rate unknown. wfa peak b-field -- 22 1pe9.2 format Waveform Analyzer (WFA) peak magnetic field intensities from 22 frequency channels. These values represent the highest intensities measured over the sampling interval. Below is a list of the center frequency for each channel: F(1): 0.22 Hz F(2): 0.33 Hz F(3): 0.44 Hz F(4): 0.66 Hz F(5): 0.88 Hz F(6): 1.33 Hz F(7): 1.77 Hz F(8): 2.66 Hz F(9): 3.55 Hz F(10): 5.33 Hz F(11): 9.00 Hz F(12): 14.00 Hz F(13): 19.00 Hz F(14): 28.00 Hz F(15): 37.00 Hz F(16): 56.00 Hz F(17): 75.00 Hz F(18): 112.00 Hz F(19): 149.00 Hz F(20): 224.00 Hz F(21): 299.00 Hz F(22): 448.00 Hz Missing data flag value ----------------------- Any data column whose value is -9.99e+10 is a missing data value. Data Description ================ GUIDE TO THE ARCHIVING OF ULYSSES RADIO AND PLASMA WAVE DATA Roger Hess, Robert MacDowall, Denise Lengyel-Frey March 15, 1995 Contents 1 Introduction 3 2 Delivery Schedule 3 3 Description of the Unified Radio and Plasma Wave Instrument 4 3.3 Waveform Analyzer 5 4 World Wide Web Access to URAP Data 7 APPENDICES 8 A UDS data files 8 A.4 Waveform Analyzer Magnetic Field 15 1 Introduction The Unified Radio and Plasma wave instrument (URAP) is designed to detect both remotely-generated electromagnetic waves and in-situ plasma waves. The former are radio waves arising from electron beams in the solar wind (type II and type III radio bursts), planetary radio emissions (from Jupiter, the Earth, etc.), and a cosmic background from the local galactic medium. The in-situ waves include thermal plasma fluctuations, electron plasma oscillations (Langmuir waves), ion-acoustic waves, and whistler-mode waves. Wave electric fields from less than 1 Hz to 940 kHz and magnetic fields from less than 1 Hz to 448 Hz can be measured. An extensive description of the five instruments that make up the URAP investigation can be found in [STONEETAL1992A]. Details relevant to the data archive are contained below. The Astron. Astrophys. Suppl. Ser. issue also contains other articles describing the Ulysses spacecraft as a whole and the other Ulysses instruments. Ulysses is spun for stability with a period of approximately 12 sec. The Z axis of the spacecraft is defined as being along the spin axis. The X and Y axes are perpendicular to the spin axis. URAP measures electric field by means of two antennas. One is a dipole formed by two 35 meter long wires along the +/- X axes and the other is a 7.5 meter long monopole that is on the Z axis Because of the longer length of the X antenna compared to the Z antenna, it is much more sensitive and has a much lower background signal level. For these reasons, only the X antenna data are provided in the UDS data files. Magnetic fields are measured by means of a two axis sensor aligned along the spacecraft Y and Z axes. 2 Delivery Schedule The URAP team will provide the archival data products to the Ulysses Data System no later than 2 months after GSFC has received the raw data. These data will be provided to the NSSDC no later than 1 year after GSFC has received the raw data. 3 Description of the Unified Radio and Plasma Wave Instrument The Unified Radio and Plasma Wave instrument on Ulysses is divided into several sub-instruments. Data from three of these sub-instruments, the Radio Astronomy Receiver, the Plasma Frequency Receiver, and the Wave Form Analyzer, are represented in the URAP archival data. 3.3 Waveform Analyzer The Waveform Analyzer (WFA) measures electric and magnetic signals in the frequency range from 0.08 to 448 Hz. The WFA divides the spectrum into a low and a high band and the analysis is performed separately for the two bands. The low band consists of the frequencies 5.33 Hz and below and the high band consists of frequencies 9.3 Hz and above. The high band processing is performed on Ex, By, and either Bz or Ez depending on a mode command. The information is digitized at a sample rate of 1.792 kHz. Spectra are produced and summed for 2 formats of spacecraft telemetry (64 seconds at the highest telemetry rate). The amplitudes at 12 frequencies are determined using a modified Walsh transform with a bandwidth of 25%. A spectrum is taken for each octant of spacecraft rotation. There are generally 5 or 10 rotations during the 2 format major cycle (depending on the current telemetry bit rate). One set of data obtained, called the averaged data, is the sum of these 5 or 10 spectra per octant, which are then grouped together by opposite octants, giving 4 spectra per antenna. Another set of data, called peak data, is obtained by taking the largest values recorded for the Ex antenna for each frequency and octant, and the values of By and Bz or Ez taken at the same time. Signals for the low band are obtained from Ex and either By or Bz depending on a mode command. The sample rate of the signals is 256 times per spin of the spacecraft and a spectrum is produced every 16 telemetry frames, representing one spin. The same averaging/peak algorithm as the high band is used to on the low band. 4 World Wide Web Access to URAP Data Some of the URAP data are being made available over the World Wide Web (WWW). By this means, the data are made convenient and quick to use by a much larger audience, including anyone with access to the Internet. The URAP home page on the WWW provides more information for those interested. The home page makes available color dynamic spectra of the RAR data and information on the location of Ulysses during the mission. Educational material and a bibliography of papers describing Ulysses and URAP are also provided. The home page also gives links to other WWW sites of interest including NASA, Goddard Space Flight Center, the Jet Propulsion Laboratory and the European Space Agency, as well as other investigators using the Ulysses instruments and data. The Universal Resource Locater for the URAP home page is http://urap.gsfc.nasa.gov/www.urap_homepage.html APPENDICES A UDS data files Eight files are provided that conform to the UDS conventions regarding the naming of files and the format of the data. The eight files are divided into 4 pairs of files with each pair consisting of a file containing data averaged over a 10 minute period and a file containing the maximum data value during the same 10 minute period. The 4 pairs of file contain data for the RAR, the PFR, WFA - magnetic field, and WFA - magnetic field. A.4 Waveform Analyzer Magnetic Field The names of the files are (following the UDS convention): Tyyddd.TAB -> Peak data yy: Last two digits of year. ddd: Day of year (1..366). The files are Ascii and contain one line for each time period (even if there are no valid data for a time period) so they contain 144 lines each. The format of the data is indicated by the following Fortran read statement (which can be used to read the files): DIMENSION F(22) READ(1,100) IYEAR,IDOY,IHOUR,IMIN,ISEC, +IPFRMODE,IANTENNA,IBPS,F 100 FORMAT(I4,4(1X,I2),F6.3,3X,3I1,22(1X,1PE11.4)) The variables are defined as follows TIME : Spacecraft event time in the format yyyy-mm-ddThh:mm:ss.sssZ. ANTENNA: Antenna used for low band (0.22 to 5.33 Hz). The high band (9.8 Hz and above) is always By. 1: By 2: Bz 3: Antenna switched during the averaging interval. 4: Antenna unknown. PFRMODE: Indicates the scan mode of the PFR instrument. 1: Fast scan mode. 2: Slow scan mode. 3: Fixed-frequency mode. 4: The mode switched during the averaging interval. 5: The mode could not be determined. BPS: Telemetry bit rate: 1: 128 bps. 2: 256 bps. 3: 512 bps. 4: 1024 bps. 5: Bit rate changed during averaging period. 6: Bit rate unknown. F: Contains the data for By or Bz (peak values) of the 22 frequency channels. The frequencies are: F(1): 0.22 Hz F(2): 0.33 Hz F(3): 0.44 Hz F(4): 0.66 Hz F(5): 0.88 Hz F(6): 1.33 Hz F(7): 1.77 Hz F(8): 2.66 Hz F(9): 3.55 Hz F(10): 5.33 Hz F(11): 9.00 Hz F(12): 14.00 Hz F(13): 19.00 Hz F(14): 28.00 Hz F(15): 37.00 Hz F(16): 56.00 Hz F(17): 75.00 Hz F(18): 112.00 Hz F(19): 149.00 Hz F(20): 224.00 Hz F(21): 299.00 Hz F(22): 448.00 Hz These data are magnetic field intensities detected by the Waveform Analyzer (WFA) on the URAP instrument. Units: 10**-15 Tesla/Hz**0.5 Time resolution: 10 minutes Fill value for bad or missing data is -9.99e+10.