ResourceName
CNOFS CINDI IVM 500 ms Ion Drift Data
DOI
https://doi.org/10.48322/r9x4-x639
ReleaseDate
2023-07-30 12:34:56.789
RevisionHistory
RevisionEvent
ReleaseDate
2021-04-27 15:38:11
Note
Only known prior ReleaseDate of the metadata
RevisionEvent
ReleaseDate
2023-07-30 12:34:56.789
Note
Added DOI and PublicationInfo minted by LFB, metadata versioned up to SPASE 2.6.0, reviewed by LFB 20230727
Description
This data set contains plasma parameters of the equatorial F-region in the ionosphere measured by the Ion Velocity Meter (IVM) of the Coupled Ion-Neutral Dynamics Investigation (CINDI) payload on board the CNOFS spacecraft. Data are available in HDF format, with an IDL program to read and plot them. Each file contains data from one day of spacecraft operation and the file contains eight primary geophysical parameters: the ion temperature (Ti) in degrees Kelvin, the ion flow in m/s in the ram (i.e.--spacecraft velocity) direction (+Vx in the direction of spacecraft velocity), the ion flows in m/s in the horizontal and vertical directions (Vy and Vz) at right angles to the ram direction (+Vz is downward, +Vy is roughly southward), the total ion density (Ni) (the sum of O+ and H+ and He+ concentrations) in ions/cc, and the individual H+, He+, and O+ concentrations in ions/cc. In addition, ion velocities also are given in the coordinate system of the local magnetic field (parallel, perpendicular, and meridional) in the plots and as ASCII data on the UT Dallas website. Based on the IGRF model, the data are transformed into magnetic coordinates only if all three ion velocities in the spacecraft coordinates are available and good.
Acknowledgement
Please acknowledge NASA SPDF and the CINDI team at the University of Texas at Dallas that is supported by NASA grant NAS5-01068
PublicationInfo
Authors
Heelis, Roderick, A.
PublicationDate
2023-01-01 00:00:00
PublishedBy
NASA Space Physics Data Facility
Contacts
PriorIDs
spase://VSPO/NumericalData/CNOFS/CINDI/IVM/PT0.5S
In general the ion temperature and densities can be trusted to be valid throughout the entire orbit and at all altitudes. However the flow data can only be trusted at lower altitudes. The analysis of the ram velocity becomes more uncertain as the percentage of the light ions becomes predominate. Under those conditions, the analysis routine sets Vx to zero and solves for the other parameters. Note that the Vy or Vz data are also removed here since the drift meter does not produce usable data under these conditions. Likewise the crosstrack ion drift meter only works reliably when the percentage of O+ is very high and since the percentage of O+ decreases with increasing altitude, therefore the best crosstrack data come in the region near perigee and on the dayside. However, data from perigee on the nightside or near apogee on the dayside can also be acceptable, depending on the ambient O+ densities. Be certain to read the CINDI Quality Flag Description document and check the individual RPA and DM quality flags for each record before using the data. Also, please do not use these data in a presentation or publication without first checking with one of the CINDI researchers.
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