Plot Types in the obsolete version. More browse data products are available in the updated version.
Where are missing plots?

The links below point to day by day links to various kinds of 24 hour summary plots in 'gif' format. The text below the full set of date links describes the plot formats and explains why some plots are missing.

The active links above point to day by day pointers for various kinds of 24 hour summary plots in 'gif' format. The text below describes the plot formats and points out why some plots are missing.

Back to the TIMAS home page

• Key Parameter (KP)
• Mass Spectra at selected energies (MS)
• omnidirectional Flux energy-time sepctrograms (FLX)

There are several reasons for missing plots.

• TIMAS data really are not available...Check the Major Event Log

  Currently after December 8, 1998 only MS summary plots are avilable because of a high voltage anomaly. We are in the process of recalibrating the instrument.

• TIMAS data are currently unuseable...Check the list of bad data intervals
• We've run into a feature in our plotting codes that prevents making plots for that day.
• We haven't processed the interval yet.

The KP (key parameter) 24 hour summary plot has 5 panels. example kp plot
More information about TIMAS Key Parameters (including pointers to three different software packages to access them) is available on-line

Only a few of the quality and density key parameters are given on the KP summary plot.

NOTES:A low value of the H+ quality parameter indicates that either the H+ signal detected by TIMAS is too low for reliable measurements or the background counting rate is too high for reliable measurements. The full timas key parameter data set contains data quality parameters for each mass constituent.

    The Three KP Energy Ranges are TIMAS mode dependent
    The TIMAS KP Velocity Coordinate system is non standard 
    The NASA CDAWeb Provides graphical displays of 
	Additional TIMAS Key Parameters

• The top panel presents the H+ density from the complete energy range sampled by the TIMAS instrument. Depending on the the date and instrument mode this could be:
  • 0.015-22 keV/e (reduced energy used from 3/17 to 17:35 on 6/26/96)
  • 0.015-33 keV/e (full energy mode used after 6/26/96.
  • Becasue of on-board software anomolies, data from the 0.015-2.2 keV/e low energy range mode are not available in the TIMAS key parameter data set.
• The second panel presents the He++/H+ density ratio
• The third panel presents the O+/H+ density ratio
• The fourth panel presents the He+/H+ density ratio
• The bottom panel presents the geometic average of the three H+ quality parameters.
• IMPORTANT:A low value of the H+ quality parameter indicates that either the H+ signal detected by TIMAS is too low for reliable measurements or the background counting rate is too high for reliable measurements. The full timas key parameter data set contains data quality parameters for each mass constituent.
  

The position of the detetable mass groups (H+, He++, He+, O+, and Moleculars-- N2+, O2+, and N0+) in the mass step range 0-63 changes with energy. For the example plot, in the lowest energy chanel (MS1) H+ is at mass step ~8 and O+ is at mass step ~29. In the higest energy chanel (MS8) H+ is at mass step ~32 and O+ is at mass step ~50. A flux of molecular ions can be seen in MS2 above the O+ line just before 12:00 UT.

Below the MS1 color panel are three line plots and a panel labeled ICP. The top line, BCR is a line plot of the log of the total background counting rate as a function of time. The E RANGE line indicates the instrumental energy range, Full 0.015-33 keV/e (Red/top), Reduced 0.015-22 keV/e (Yellow/mid) or Low 0.015-0.22 keV/e (Green/bottom). The ICP Number in the next panel indicates the operating mode. In the Example MS Plot the mode switched from 6 to 5 at ~ 07:00 and back to 6 at ~13:00.

If the two lines indicated by BAD are filled by RED (not on the sample plot), The mass spectral data are OK, but data in the PAD, LRDF, and MRDF data products are unuseable. Key parameters are derived from the LRDF data products and so will be missing for such intervals.

Universal Time (UT), the satellite geocentric distance in R/re (R), The MacIlwain L parameter (LVAL), the eccentric dipole magnetic local time (EDMLT) and the geomagnetic latitude (MLAT) are given at the bottom of the plot.

The energy bands displayed are time and mode dependent.

Before 20:00 on 9/3/96:

Data gaps appear because of spacecraft or instrumental anomalies which are noted in the Timas major event log

The center energies of each of the 28 fundamental channels cover the range from 25 eV/e to 32 keV/e. The lower limit of energy acceptance is 16 eV/e above the spacecraft potential. The upper limit of energy acceptance is 33 keV/e.

Below the He++ Head B color panel are three line plots and a panel labeled ICP. The top line, BCR is a line plot of the log of the total background counting rate as a function of time. The E RANGE line indicates the instrumental energy range, Full 0.015-33 keV/e (Red/top), Reduced 0.015-22 keV/e (Yellow/mid) or Low 0.015-0.22 keV/e (Green/bottom). The ICP Number in the next panel indicates the operating mode. In the Example FLX Plot the mode switched from 6 to 5 at ~ 07:00 and back to 6 at ~13:00.

NOTE: In regions of high background counting rate, slight errors in our background correction routine can lead to erroneously high or low fluxes being encoded on these plots.

If the two lines indicated by BAD are filled by RED (not on the sample plot), The mass spectral data are OK, but data in the PAD, LRDF, and MRDF data products are unuseable. Key parameters are derived from the LRDF data products and so will be missing for such intervals.

Universal Time (UT), the satellite geocentric distance in R/re (R), The MacIlwain L parameter (LVAL), the eccentric dipole magnetic local time (EDMLT) and the geomagnetic latitude (MLAT) are given at the bottom of the plot.

Data gaps appear because of spacecraft or instrumental anomolies which are noted in the Timas major event log

Data is intermittent after October 29, 1999, becasue of a problem in the parts or cabling associated with the partially redundant telemetry interface. A request to the project to switch to use the redundant telemetry interface during the fall 2000 inversion maneuver was made in April, 2000. If the problem is associated with parts or cabling in the redundant interface we expect the telemetry drop outs will end.

Data quality in the intervals after October 29, 1999, remains high. A presentation to the Polar science team illustrating the TIMAS data quality was made in November, 2000.

A request for an assessment of the risks associated with switching to the redundant telemetry interface was made by the Polar project scientist in July, 2000. We note that the polar redundant telemetry system was extensively tested before launch and that a similar system on the wind spacecraft is currently the active wind telemetry system.

A meeting was held December 4, 2000 where the hardware and operations risks for performing a switch to Side B telemetry were disucssed. At the meeting no single point failures were identified from which it would not be possible to recover normal operations.

A teleconference of Polar PI's was held January 12, 2001. Part of this conference was devoted to clarifying information distributed to the PI's regarding the project mailing with the FOT's assesment of the risks associated with a switch to side B tm. PI's were asked to express thier opinions about pursuing a switch by close of business on January 19, 2001.

The vote of the PI's in response to the questions posed by the project relating to the GTM swith was 10 in favor and 2 votes with held. A memo requesting permission to proceed was drafted and started on its way through the approval cycles at Goddard and Headquarters on 1/22/01. With luck, approval and operations planning will be complete in time to make the switch at the Spring inversion maneuver in March 01.

The last item in the long list of items required to perform the TM switch was a formal letter from the director of Goddard to NASA Headquarters acknowledging the planned switch. It was sent on 3/23/2001, just a few days before the switch.

The GTM switch was succsfully made and TIMAS data recovered!

TIMAS Telemetry recovered 3/30/2001