1. Status Report of the WBD Experiment for the CAA Operations Review Board 20 May 2008
Jolene S. Pickett, Joanne M. Seeberger, and Ivar W. Christopher
Department of Physics and Astronomy
The University of Iowa
Iowa City, IA, USA
Contents
1. Introduction
2. Status of the instrument data products delivery
3. Status of the instrument calibration and cross-calibration activity
4. Status of software development: status and delivery to the CAA
5. Status of documentation delivery
6. Overview of the archiving activity for the extension
7. Open issues, problems
8. Summary
Acknowledgments: NASA/Goddard Space Flight Center

2. OVERVIEW OF THE WBD INSTRUMENT AND DATA CHAIN
1. Introduction - 1
OVERVIEW OF THE WBD INSTRUMENT AND DATA CHAIN
Transmit to Ground (220 kbits/s) *
WBD INSTRUMENT
Make waveform measurement using appropriate mode for region
Antenna Bandwidth
Ez kHz
Ey kHz
Bx kHz By
Conversion Freq. Resolution
0 kHz (Baseband) bits
kHz bits
kHz bit
kHz
Input Wave
DSN or Panska Ves
Receive and record data
ftp transfer
The University of Iowa
Level 1 Processing
Creation of L1 files
Validation of L1 files
Write L1 files to DVD
* NOTE: WBD data have never been recorded onboard with one exception: March 7, 2001 in the WBD burst mode
Mail DVDs
Local Institute
Analyze waveform
Or convert to frequency domain for spectral analysis (FFT, wavelet, etc.)
Extract L1 data
French, Swedish and UK Cluster Data Centers, Stanford University, SwRI

3. Example of Chorus Waveforms from 3 spacecraft
1. Introduction - 2
Example of Chorus Waveforms from 3 spacecraft
WBD is best suited for detailed analysis of the fine structure of linear and nonlinear waves observed throughout the orbit in support of:
- Wave Experiment Consortium (WEC) objectives and complementary to the WHISPER and STAFF-SA instruments
- WBD-specific objectives such as Very Long Baseline Interferometry (VLBI) and cross-spacecraft waveform correlation

4. 1. Introduction - 3
Summary of the status of the archive for WBD at the CAA:
Documentation: Archiving completed, except for updates of some time listings on a best efforts basis
Software: Archiving completed
Data:
Overview spectrograms: Archiving completed for first four years of mission (1 Feb – 31 Jan. 2005)
High resolution spectrograms: Archiving completed for first four years of mission

5. 1. Introduction - 4 Management at Iowa: Science:
Jolene Pickett, WBD Principal Investigator
Ivar Christopher, WBD Operations Manager
Technical:
Joanne Seeberger, WBD Data Manager
Administrative: Robert Neppl

6. 1. Introduction – 5 Action Items from OR-2 Review (May, 2006):
R41: We recommend that the digital data be made available to the CAA. The WBD team should discuss with the CAA the best way to provide this data.
Numerous conversations took place between the CAA, Iowa and Goddard Space Flight Center in January and February 2008 regarding the best way to provide the WBD data set to the CAA, should augmentation funding be received by Iowa to carry out the archiving, given its enormous size already (several TBytes). It was decided as a minimum to produce cdf files of the digital time series data for archival at the US Cluster Data Center (CDAWeb) and either transfer these files to the CAA for conversion to cef format or create cef files at Iowa or CDAWeb using the cdf files and transfer the cef files to the CAA. This action item should be closed.

7. 1. Introduction - 6 Action Items from OR-2 Review (May, 2006) (cont.):
R42:We note that there will be a NASA Senior Review in February We recommend that support is requested from NASA for US instrument teams, including WBD, to provide data to the CAA. ESA and the board would provide their full support to such a bid.
The Cluster NASA Senior Review proposal was submitted to NASA on 21 Feb and presented to the Senior Review Board on 8 Apr The proposal contained a request for augmentation funding for Iowa to create WBD digital data files in cdf format for archival at the Cluster US Data Center (CDAWeb) and for either Iowa or CDAWeb to transfer the cdf files to the CAA for conversion to cef, or for Iowa to convert the cdf files to cef and deliver the cef files to the CAA. This action item should be closed with respect to WBD.

8. 2. Status of the Instrument Data Products Delivery - 1
Two types of WBD data plots are already archived at the CAA:
Overview Spectrograms
Variable length (~0.5-6 hours)
Multi-panel (one panel for each spacecraft for which there are WBD data)
Postscript and png formats available
High resolution Spectrograms
30-seconds in length
Single spacecraft
Instrument mode data contained at top of plot
Gif format

9. 2. Status of the Instrument Data Products Delivery - 2
OVERVIEW PLOTS
Range from about 0.5 – 6 hours
Show WBD spectral data (using FFT) from all spacecraft being sampled for the interval
Used to identify events for in depth study
Available as png files, e.g.:
CM_CG_WBD_SPECPLOT_OVERVIEW_PNG_ _1036_V00.PNG
Postscript versions made but not yet available
CAA contains 1 Feb 2001 thru 31 Jan 2005

10. 2. Status of the Instrument Data Products Delivery - 3
GIF PLOTS
30-second, full resolution
Show spectral data (via FFT on ground) from only one spacecraft
Top panels shows instrument mode
Used to resolve fine structure of waves
Available as gif files, e.g.:
C4_CG_WBD_GIFPLOT__ _0910_ _0911_V00.gif
CAA contains 1 Feb 2001 thru 31Jan 2005

11. 3. Status of the Instrument Calibration and Cross-Calibration Activity - 1
WBD instruments are fully calibrated
Calibration does not change over time
Calibration is applied in the time domain and is thus frequency independent
Iowa does not anticipate developing a frequency-dependent calibration because the filter response is nearly flat across the entire frequency bandpass (minor fall-off at edges of filters).
Electric field calibration assumes a physical antenna length of 88 m, whereas the effective length may in fact be less than that in some regions. Units are mV/m
Magnetic field calibration is in nT

12. 3. Status of the Instrument Calibration and Cross-Calibration Activity - 2
Waveform cross-calibration previously carried out with EFW, which identified some timing, sign (of E-field) and receiver response issues which have been dealt with
Power Spectral Density cross-calibration previously carried out with Whisper and STAFF with good agreement
Currently working on cross calibration with PEACE of densities in low density regions (primarily below WHISPER cutoff frequency)
WBD uses the wave L-X mode cutoff frequency to obtain the plasma frequency
Densities for several time intervals from have been compared to PEACE with mixed results – variations are still being investigated
Will identify 2007 events soon and obtain densities

13. 4. Software development: status and delivery to the CAA - 1
FIX_SC2.C C code to identify known bad data points in the time series, and then average across adjacent points (already delivered).
Problem originates within the Onboard Data Handling System and was discovered from data obtained while the s/c was on the launch pad and thus not fixed.
CALIBRATE.C C code to calibrate the WBD Level 1 data (already delivered).
Calibration is applied in the time domain and is thus frequency independent.

14. 4. Software development: status and delivery to the CAA - 2
EXAMPLES Directory (already delivered):
EX_README.TXT Explanation of how to use the software
CLOG.C Example C code to output a list of all data modes contained in a Level 1 file (if no mode changes, only one line is output)
PARSETIME.C C code used to parse the data (needs to be linked to RD_WBD_WF.C)
RD_WBD_WF.C Example C code to read the Level 1 data files and output the calibrated data in binary format
WBDL1LIST.C Example C code to extract and list most fields contained in the Cluster WBD Level 1 file records
WBDL1.H Contains macros, tables, etc. for use in processing Cluster WBD Level 1 data
MAKEFILE Converts to Unix-friendly format, compiles the programs, runs the programs, and outputs data

15. 4. Software development: status and delivery to the CAA - 3
EXAMPLES Directory (already delivered) (cont.):
C1 Test Level 1 file
WBDL1LIST _9C1.TXT Output listing of all field values in file
CLOG _9C1.TXT Output listing of all data modes found
R_WBD_WF TXT Output Data File (waveform data only)
Iowa does not anticipate archiving any further software at this time.

16. 5. Status of WBD Documentation Delivery - 1
Documentation Already Delivered to CAA:
General Documentation:
WBD ICD Version 2.1 [pdf]
WBD Data Coverage Files (listings of times and modes of WBD data availability, ~ 24 hours/week) [txt and html]
Listing of times of Coordinated Cluster WBD/PEACE Chorus Operations [html]
Listing of times of Coordinated Cluster WBD/WHISPER/PEACE Nonthermal Continuum Operations [html]
Listing of times of Other Special Operations (HAARP, IMAGE RPI Transmissions, Mutual Impedance tests) [html]
Cluster WBD Interpretation Issues [pdf] – see example next slide
WBD Calibration [pdf]

17. 5. Status of WBD Documentation Delivery - 2
Example from: Interpretation Issues document
GAIN AMPLIFIER SWITCHING: 3 specific automatic gain state changes introduce:
- ringing (artificial pulses) - intense broad bands
in the waveforms in the frequency domain

18. 5. Status of WBD Documentation Delivery - 3
Documentation Already Delivered to CAA (cont.):
Documentation associated with and included on the WBD Level 1 DVDs:
Instrument Description [txt]
Description of the format of the Cluster WBD LEVEL1 data files [txt]
Description of the contents of a Level 1 data DVD volume [txt]
List of known problems and anomalies in the data [txt]
Description of the origin of time stamps, their accuracies, and their preferred applications [txt]

19. 5. Status of WBD Documentation Delivery - 4
Documentation still to be delivered (if funding received):
Coverage Files for 2005 to present [txt and html]
Updated Listing of Coordinated Cluster WBD/PEACE Chorus Operations (to include 2005-present) [html]
Updated Listing of Coordinated Cluster WBD/WHISPER/PEACE Nonthermal Continuum Operations (to include 2005-present) [html]
Updated Listing of Other Special Operations such as HAARP (2005-present) [html]
Reference in connection with Interpretation Issues: “WBD Response to Bipolar and Tripolar Pulses: Bench Tests vs. in Flight Observations”, by J. M. Swanner, J. S. Pickett, J. R. Phillips, and D. L. Kirchner [pdf]

20. 5. Status of WBD Documentation Delivery - 5
Sample from Coverage File: wbd_mop.jan_apr2002
Purpose: Used to determine if WBD data are available for a specified time and in the desired instrument mode
START TIME STOP TIME S/C CONV. B/W ANT. RES.
=================================================================
T00:30:03.210Z T02:40:38.383Z C4 0 kHz 9.5 kH Ez 8 bits T00:30:58.546Z T02:40:00.777Z C2 0 kHz 9.5 kH Ez 8 bits T16:54:57.888Z T17:55:12.163Z C2 0 kHz 9.5 kH Ez 8 bits T16:55:04.359Z T17:55:35.873Z C4 0 kHz 9.5 kH Ez 8 bits T03:05:07.895Z T05:40:12.657Z C3 0 kHz 9.5 kH Ez 8 bits T03:46:03.334Z T05:40:00.934Z C4 0 kHz 9.5 kH Ez 8 bits T11:18:00.176Z T12:52:32.591Z C4 0 kHz 9.5 kH Ez 8 bits T11:42:37.387Z T12:50:01.020Z C2 0 kHz 9.5 kH Ez 8 bits T02:55:06.333Z T05:00:00.845Z C4 0 kHz 77 kHz Ez 8 bits T02:56:58.330Z T05:00:48.179Z C2 0 kHz 77 kHz Ez 8 bits T18:47:47.860Z T18:49:20.484Z C4 250 kHz 9.5 kH Ez 8 bits T18:49:20.524Z T18:50:11.959Z C4 500 kHz 9.5 kH Ez 8 bits T18:50:11.999Z T18:51:08.677Z C4 125 kHz 9.5 kH Ez 8 bits T18:51:08.717Z T18:52:51.787Z C4 250 kHz 9.5 kH Ez 8 bits T18:52:51.827Z T18:53:43.262Z C4 500 kHz 9.5 kH Ez 8 bits =================================================================

21. 6. Overview of the archiving activity for the extension -1
WBD will archive overview and high resolution plots plus data coverage and special event listings for 1 Feb to present on a best efforts basis (or definitely if augmentation funding is received)
If augmentation funding is received from NASA by Iowa, Iowa will:
Create WBD digital data files in cdf format containing:
Time tags (20 microsecond accuracy; ground-based and WEC-corrected onboard based),
Instrument mode,
Gain (needed for converting calibrated data back to data numbers 0-255),
Calibrated time series data,
Quality parameters,
Sample rate (needed to convert to frequency domain),
Two angles relating the measurement to the magnetic field direction and to an earth-sun based coordinate system.

22. 6. Overview of the archiving activity for the extension - 2
If augmentation funding is received from NASA by Iowa, Iowa will (cont.):
Archive the cdf files at CDAWeb (the site of the Cluster data center in the U.S.)
Arrange for transfer of these cdf files to the CAA for conversion to cef format by the CAA, or create cef format files at Iowa to transfer to the CAA (details to be finalized if funding received)
A sample one hour cdf file of Polar wideband data (similar to Cluster WBD) has recently been sent to the CAA for conversion to cef to check size and assess the viability of the process
Even though only hours of WBD data are received each week, due to the high bit rate of the data, there are already several TBytes of data.

23. 7. Open issues and problems - 1
A small Living With a Star (LWS) grant was received by Iowa to archive the WBD documentation, software and first four years (1 Feb – 31 Jan. 2005) of standard data plots.
WBD has never been funded through its NASA Goddard Space Flight Center MO&DA grant to archive data, documentation and software at the CAA
Augmentation funding to create cdf files of the entire WBD data set and archive them at CDAWeb was requested in the Cluster proposal that was submitted and presented to the NASA Senior Review Board on 8 April 2008 (still waiting for decision)
If augmentation funding is received, Iowa will archive documentation and plots at the CAA from 2005 to present, as well as arrange for the times series data to be archived at the CAA.

24. 7. Open issues and problems - 2
If augmentation funding is made available by NASA, the data delivery schedule will depend on the time needed to process and validate all existing data (> 7 TB for ) and data taken during the rest of the mission
Experience with the Polar wideband data suggests that a minimum of two years will be needed to complete the archiving of the cdf files for , with a third year to do 2008 and get up to date
Assuming 1 Oct as a reasonable start date for this activity, we propose the following schedule:
Deliver all data to the CAA by December 2010
Deliver the rest of the WBD data (through then most recently acquired data) by December 2011.

25. 7. Open issues and problems - 3
Until the WBD time series is available in the CAA, all WBD data are available as follows (CAA should provide this information with links):
Go to the WBD home page
and request a digital download from the “Data Analysis and Planning Tools” block on the left hand side of the page (ascii file only) – see next slide
Download and use the software archived at the CAA and obtain the Level 1 data files from Iowa, SwRI or one of the WEC data centers in Europe
Request calibrated data files from Iowa or SwRI
Display and download overview and high resolution spectrograms for 1 Feb 2005 to present from the WBD web site – see next slide

26. 7. Open issues and problems - 4
WBD Survey Plots
Digital Data Download Tool

27. 7. Open issues and problems - 5
Sample output file

28. 8. Summary
All of the documentation needed to understand the WBD data, all WBD software useful in reading and calibrating its Level 1 data files (which can be obtained at the WEC and US data centers), and overview and high resolution plots for the first four years of the mission have been archived and are available at the CAA
Iowa firmly believes that the WBD digital time series data files, in standard CAA format, should be made available through the CAA and is attempting to obtain funds for that purpose through the NASA Senior Review process
Until the WBD data are available in the CAA, we strongly encourage everyone to get them from one of the other sources previously mentioned and use them in their studies
The WBD “Interpretation Issues” document should be downloaded from the CAA and consulted when carrying out research with WBD data

29. EXAMPLE 2: INTERPRETATION ISSUES AND CAVEATS
EDI INTERFERENCE: Observed at constant characteristic frequencies and multiple harmonics associated with the EDI mode

30. EXAMPLE 3: INTERPRETATION ISSUES AND CAVEATS (cont.)
BATTERY SUBSYSTEM INTERFERENCE: Observed at constant frequency around 65 kHz and harmonics in the electric data
Battery Subsystem Interference

31. EXAMPLE 4: INTERPRETATION ISSUES AND CAVEATS (cont.)
WEC DWP CLOCK INTERFERENCE: Observed at constant frequency around 900 Hz and harmonics in the magnetic data
DWP Clock Interference

32. EXAMPLE 5: INTERPRETATION ISSUES AND CAVEATS (cont.)
WHISPER SOUNDINGS:
Ringing-type effects observed in the waveform; Intense broad bands in the frequency domain

33. EXAMPLE 6: INTERPRETATION ISSUES AND CAVEATS (cont.)
CLIPPING (due to limit of 8 bits) AND RECEIVER SATURATION: Harmonics are instrumental as opposed to natural

34. EXAMPLE 7: INTERPRETATION ISSUES AND CAVEATS (cont.)
INSTRUMENTAL EFFECTS: Believed to originate at the electric field booms in certain types of plasmas and are not natural

35. EXAMPLE 8: INTERPRETATION ISSUES AND CAVEATS (cont.)
MULTI-POLE FILTER RESPONSE TO PULSES:
Get distortion as pulse duration approaches the RC time constant of the filter system
Result: Pulse duration (and thus frequency) are not accurately measured
A document describing this will be submitted to the CAA
Bipolar pulse in (345 us); bipolar pulse out
Bipolar pulse in (1700 us); tripolar pulse out