1. Status Report of the WBD Experiment for the CAA Operations Review Board 30-31 May 2012
Jolene S. Pickett, Joanne M. Seeberger, Ivar W. Christopher and Roxane M. Mitten
Department of Physics and Astronomy
The University of Iowa
Iowa City, IA, USA
Contents
1. Introduction
2. Management
3. Status of Software Development
4. Status of Experiment Calibration/Cross-Calibration
5. Status of Dataset Delivery
6. Data Delivery Plan for the Remaining Years
7. Documentation
8. Replies to the Recommendations of the 6th Operations Review
9. Status of Action Items
10. Open issues
Acknowledgments: NASA/Goddard Space Flight Center

2. 1. Introduction -1
WBD measures the AC electric (100 Hz – 577 kHz) and magnetic field (70 Hz – 4 kHz) (upper frequency limit constrained by STAFF search coils) along one axis at very high time resolution (~27 – 220 ksamples/s).
These data are telemetered directly to DSN and Panska Ves ground stations (apart from a few burst mode 2 operations where the WBD data were recorded onboard with the data from the other instruments).
WBD data are received from only ~ 4% of any one orbit (25-45 hours per week across all spacecraft).
The WBD team at the University of Iowa processes the raw data to obtain highly accurate time tags (order of 50 microseconds) and writes the uncalibrated data and time tags to Level 1 data files.
These Level 1 data files are used as the basis for creating the WBD calibrated waveform (time series) CDF files archived at the CAA.

3. 1. Introduction -2
Two types of pre-generated plots created during the Level 1 process (overview/survey and high resolution) are also archived at the CAA.
The WBD team has generated and submitted to the CAA standard format documents: Interface Control Document, User Guide and Calibration Report.
The WBD team has also generated and archived specialized documents, such as listings of times of WBD operations (Coverage and Science Summary), Interpretation Issues, Caveats, and listings of special operations carried out with other instruments or missions.
The WBD team has participated in cross calibration activities in the past to the extent permitted given the limited amount of funding available for archiving efforts in general, but nothing in that regard has been done this past year.
All aspects of the WBD investigation (planning, scheduling and commanding of operations, and data processing, archiving and analysis) are funded solely by NASA Goddard Space Flight Center.
The following slides are focused on the progress made by the WBD team with regard to CAA activity since May 2011.

4. 2. Management - 1 Management at Iowa:
Science (no changes since May 2011):
Jolene Pickett, WBD Principal Investigator
Ivar Christopher, WBD Operations Manager
Technical (no changes since May 2011):
Joanne Seeberger, WBD Archive Data Manager
Roxane Mitten, WBD Level 1 Data Manager
Administrative (no changes since May 2011):
Melissa Truong, Research Administrator

5. 2. Management - 2
NASA Contract and Funding (no changes since May 2011):
Iowa is currently working under a three-year NASA GSFC Mission Operations and Data Analysis grant covering the period November 1, 2010 through October 31, 2013.
This three-year grant includes funding for WBD’s continuing archiving efforts at the CAA and CDAWeb through October 31, 2013.
Iowa stresses that the amount funded for this work is not substantial: less than ½ FTE spread across four people whose primary work consists of WBD operations, data processing and research.
Iowa will be reliant on NASA’s continuing support of the Cluster mission in the U.S., and the WBD investigation as a major part of that, in order to complete a substantial portion of the WBD archiving effort by the end of October 2013.
If a follow-on grant is initiated by NASA for the continuing Cluster mission, Iowa will archive all data from 2010 through the end of the mission. Note that no discussion has yet taken place with Iowa regarding a follow-on grant.

6. 3. Status of Software Development
No software development is anticipated in the future
No WBD software is currently archived at the CAA.

7. 4. Status of Experiment Calibration/Cross-Calibration - 1
Only one change has been made in the calibration of WBD data since May 2011, that being to reverse the sign of the calibrated electric field measurements.
Our CDF files provide the potential difference across the two electric field spheres, , divided by the distance separating them, since WBD directly measures the potential difference.
We had neglected to add the conversion to electric field by negating the potential difference (E = - /d) after applying all the other calibration factors.
We confirmed that this sign reversal was correct by cross comparing our results for a few cases with waveform measurements made by the EFW experiment in the same frequency range.

8. 4. Status of Experiment Calibration/Cross-Calibration - 2
Since WBD measures only one electric field component, the sign of the electric field is not too important except in very limited studies involving nonlinear phenomenon.
Because of this correction in the sign of the field, Iowa will be resubmitting all CDF files previously submitted.
The WBD Calibration Report has been updated to show this correction to the calibration, as well as to provide an estimate of the error in the field amplitudes and the time tags associated with those amplitudes (Epoch).
The calibration (mV/m for electric field, nT for magnetic field) does not change over time, and is applied in the time domain and is thus frequency independent.

9. 4. Status of Experiment Calibration/Cross-Calibration - 3
Calibration (cont.):
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 only).
Electric field calibration assumes a physical antenna length of 88 m (44m on spacecraft 1 since December 2009 and on spacecraft 2 and 3 for short periods of time since May 2009 — see WBD Calibration Report), whereas the effective length may in fact be less than that in some regions.
Each user of WBD data will need to determine whether the physical antenna length is applicable for the data they are analyzing and make adjustments, if necessary.

10. 4. Status of Experiment Calibration/Cross-Calibration - 4
Cross-Calibration (cont.):
Since May 2011 WBD has carried out no cross-calibration activity, except for that required to cross check the sign of the electric field with data from similar passbands with the EFW experiment as noted under the “Calibration” subsection.
Funding for WBD activities is at a “bare bones” level and does not currently allow for cross calibration of densities obtained in low density regions as we have done in the past.

11. 5. Status of Dataset Delivery - 1
Datasets
Delivered interval
Comments
Overview spectrograms
2001 thru 2009
Available; no change since May 2011
High resolution spectrograms
WBD Waveform (CDF Files)
Feb thru Aug. 2002
Jul thru Mar. 2004
Since May 2011, delivered Aug. 2002; Jul thru Mar. 2004

12. 5. Status of Dataset Delivery - 2
We jumped from Aug (almost all conversion mode data due to large spacecraft separations) to Jul (almost no conversion mode data due to small separations) in our processing because we needed time to investigate how to properly handle the conversion mode (translation) data, i.e., representation in the time domain of data which have been downconverted from 125, 250 and 500 kHz.
There is no way to recover the original waveforms before their downconversion to base frequency (0 kHz), something that is done onboard within the WBD instrument.
Thus, we decided to keep the time scale associated with the downconversion mode.
We have included a “Warning” in the appropriate variables in the CDF files about this time scale and refer the user to our Caveats document, User Guide and Calibration Report for how to analyze these data.

13. 5. Status of Dataset Delivery - 3
The primary reasons for our not meeting our delivery schedule set last year, let alone not meeting the general schedule of all other CAA teams, are:
A considerable amount of time was spent working on the two main issues since May 2011 (electric field sign and down conversion data).
A lot of thought and time went into validating processes and optimizing procedures in order to speed up our delivery while ensuring data integrity.
Because the creation of the CAA TCOR files by the DWP team depends on the WBD Level 1 data files being available, we were forced to slow our efforts on CAA/CDF processing in order to get our Level 1 data processing and validation effort up to date so that the DWP team could meet its CAA and other wave instrument deadlines.

14. 5. Status of Dataset Delivery - 4
We now believe that all of the serious issues are behind us and that we have done everything we can to facilitate a speedier delivery schedule.
There are still three minor recurring problems remaining to be solved which affect about a handful of WBD tracks each month. These will be dealt with over the next two months.
Our goal is to deliver six months of CDF files per month starting in June 2012, and this is reflected in the schedule shown in the next section.

15. 6. Data Delivery Plan for Remaining Years - 1
Datasets
Jun. 1, 2012 – Oct. 31, 2012
Nov. 1, 2012 – Oct. 31, 2013
Nov. 1, 2013 – Oct. 31, 2014*
Nov. 1, 2014 – Jan. 31, 2015*
Overview spectrograms
2012
2013
2014
High resolution spectrograms
WBD Waveform first submissions (CDF Files)
Apr thru Jun. 2006
Sep thru Jun. 2003; Jul thru Dec. 2009
2010 thru 2013
WBD Waveform resubmissions**
(CDF Files)
Feb. 1, 2001 thru Aug. 2002
* Dependent on follow-on grant from NASA
** To correct sign of electric field and provide warning for conversion mode

16. 6. Data Delivery Plan for Remaining Years - 2
Delivery of CDF files and spectrograms for WBD data obtained in 2010 through 2014 will depend on continued funding past October 31, 2013 and could become a part of the work expected during a potential extension or phase out by NASA of WBD’s CAA efforts.
As of this date, an extension has not been discussed with Iowa.

17. 7. Documentation
Since May 2011, the following documents have been revised and submitted to the CAA to replace the documents currently existing at the CAA:
Interpretation Issues: v03
Caveats: v02
Interface Control Document: v3.2
Calibration Report: v03
User Guide: v03
WBD Coverage files for will be delivered by Oct. 31, 2012
Science Summaries [html listings of times of operations, WBD mode, science target (bow shock, magnetopause, etc.), EDI interference level] and special operations listings for 2005-EOM (End of Mission) will be delivered if time permits to update them.

18. 8. Replies to the Recommendations of the 6th Operations Review
CAA-OR6-R10: The board is concerned that the WideBand delivery plan is not consistent with the current CAA schedule, and that this may result in the failure to deliver all data products by the termination of the Active phase of the archive. The team must address these delivery issues.
Reply: The WBD team is aware and equally concerned that it may not be able to deliver all data products by the termination of the active phase of the archive. However, we started a few years later than any other Cluster instrument team, with funding at best of only ½ FTE, so it is not feasible to expect that we could meet the same deadlines as the rest of the teams even though it is our desire to do so. In addition, over the past year we have had two crucial WBD data issues to deal with and we had to respond to an OR-6 recommendation (CAA-OR6-R1). We have made every stride over the past year to speed up our process while still maintaining data integrity.
Our current plan shows that we expect that we can now begin to deliver six months of data every month to the CAA and CDAWeb, thereby achieving our original commitment to NASA of completing the archiving of WBD data obtained through Any follow-on NASA MO&DA grant would include the archiving of data received after 2009.

19. 9. Status of Action Items
CC8-AI-3, WBD/ESTEC, due 31 January 2009: to create a new WBD dataset on WBD densities. Caveat information may be needed to tell when the cut-off and the derived density are not local.
CC12-AI-13, WBD, due 31 January 2011, to provide electron densities from years
Response to both: We have no funding, and thus manpower, available at the present time in which to address these action items. Our first obligation to NASA is to process all new WBD data and continue to archive WBD data obtained through 2009 at the CAA. Unless and until funding and/or manpower become available, we will not be able to work on cross calibration activities related to obtaining densities in low density regions.

20. 10. Open Issues
Archiving of WBD data starting with Jan will depend on continued funding by NASA of the Cluster WBD experiment.
No such extension has yet been discussed with Iowa.