Version:2.4.1
NumericalData
ResourceID
spase://CNES/NumericalData/CDPP-AMDA/Rosetta/LAP/ros-lap-pho
ResourceHeader
ResourceName
Rosetta - LAP - photosaturation current (PHO)
AlternateName
Photosaturation current derived collectively from multiple sweeps
ReleaseDate
2019-09-02 13:17:49Z
Description
There are two estimates of the photoemission current from LAP1 sweeps of a sunlit probe.
I_PH0_60M in PH0 files is a statistical estimate from several sweeps (over 60 minute
windows), while I_PH0_S in the ASW files is an estimate from a single sweep with larger
uncertainties but higher time resolution (usually 160 s). As LAP1 has shown no significant
contamination effects, these estimates should be directly proportional to the EUV flux at the
Rosetta position in the 20-130 nm band [Johansson et al, 2017]. For LAP2, the same
techniques have revealed a lower photoemission at the start of the cometary phase of the
emission, and a sharp drop in photoemission after significant thruster firings (e.g. dayside
excursion, 60% decrease) with sporadic recoveries and relapses. We therefore only use LAP1
based values.
While there is no other source of photoemission measurements than LAP, its value is
controlled by solar EUV radiation which is known from e.g. TIMED and SDO at Earth and
MAVEN at Mars. Photoemission values by both methods were presented by Johansson et al.
[2017] and compared to Earth and Mars data. The two methods were found to give consistent
results, also in agreement with a third independent method immune to instrument offsets.
However, around perihelion all methods returned about 50% less photoemission than
expected from the Earth and Mars EUV fluxes. This may be a real effect, for example because
of attenuation of solar EUV radiation by large numbers of small dust grains at large distance
from the nucleus. It is also possible that this somehow relates to probe surface contamination,
though no other such effects have been noted on LAP1.
This is a preliminary data set which will be replaced by another in a few months.
Contacts
InformationURL
InformationURL
Name
RPC LAP User Guide
URL
InformationURL
Name
RPC-LAP to Planetary Science Archive Interface Control Document
URL
InformationURL
Name
RPC-LAP Report on cross-calibration of LAP data to measurements by other RPC instruments
URL
AccessInformation
RepositoryID
Availability
Online
AccessRights
Open
AccessURL
Name
CDPP/AMDA HAPI Server
URL
Style
HAPI
ProductKey
ros-lap-pho
Description
Web Service to this product using the HAPI interface.
Format
CSV
Acknowledgement
Thank you for acknowledging the use of AMDA in publications with wording like "Data analysis was performed with the AMDA science analysis system provided by the Centre de Données de la Physique des Plasmas (CDPP) supported by CNRS, CNES, Observatoire de Paris and Université Paul Sabatier, Toulouse". See the Rules of the road at https://amda.cdpp.eu/help/policy.html . Please acknowledge the Data Providers.
AccessInformation
RepositoryID
Availability
Online
AccessRights
Open
AccessURL
Name
CDPP/AMDA Web application
URL
Description
Access to Data via CDPP/AMDA Web application.
Format
CSV
Format
VOTable
Format
CDF
Format
PNG
Acknowledgement
Thank you for acknowledging the use of AMDA in publications with wording like "Data analysis was performed with the AMDA science analysis system provided by the Centre de Données de la Physique des Plasmas (CDPP) supported by CNRS, CNES, Observatoire de Paris and Université Paul Sabatier, Toulouse". See the Rules of the road at https://amda.cdpp.eu/help/policy.html . Please acknowledge the Data Providers.
ProviderName
PSA
ProviderResourceName
RO-C-RPCLAP-5-xxx-DERIV2-V1.0
InstrumentIDs
MeasurementType
ThermalPlasma
TemporalDescription
TimeSpan
StartDate
2014-03-24 09:30:00Z
StopDate
2016-09-29 00:30:00Z
Cadence
PT60S
Caveats
Quality Flag :
A quality flag is a (base 10) integer that is constructed in the two steps below:
* Add together the constants associated with the relevant quality-related effects listed below. Note that these constants are chosen such that every digit represents up to three true/false values for the presence/absence of three specific separate quality-related effects.
* Should the three quality-related effects be irrelevant for the given data product, then that digit is replaced by the digit “9”.
Quality flag event description :
* +1 - Low quality sweep analysis model fit
* +2 - One of two meanings: (1) Low sample size; an average is based on fewer data points than nominal (due to filtering or otherwise) and applies to sweep steps and downsampled time series. (2) zero-padding; zeros replace lost samples for the purpose of calculating PSD.
* +10 - One of two meanings: (1) Sweep data product and data products based on sweeps: SAA rotation of more than 0.05° during sweep. (2) Downsampled time series data product: Bias change within the 32 s downsampling period.
* +20 - Probe in partial or full shadow
* +100 - Rosetta wheel off-loading (WOL) or Orbit-control-maneuver (OCM)
* +200 - One of two meanings: (1) For LAP1: LDL disturbance (LAP2 in LDL mode); (2) For LAP2: Contamination signature possibly present
* +400 - Saturation
Example: suppose that one encounters the quality flag “109”. 109 = 100 + 9 means (1) that there is an ongoing wheel off-loading (+100), and (2) that the quality-related effects associated with +1 and +2 cannot occur even in principle for the kind of data that one is looking at.
Parameter #1
Name
i_ph0_60m
ParameterKey
ros_lap_pho
Description
Photosaturation current derived collectively from multiple sweeps
Units
A
RenderingHints
FillValue
-1.e9
Support
Parameter #2
Name
i_ph0_60m : qual
ParameterKey
ros_lap_pho_q
Description
Quality value in the range 0 (worst) to 1 (best).
Corresponds to goodness of fit or how well the model fits the data.
RenderingHints
Support
Parameter #3
Name
quality flag
ParameterKey
ros_lap_pho_f
Description
Quality flag constructed as the sum of multiple terms,
depending on what quality related effects are present. Each digit is either in
the range 0 (best) to 7 (worst), or 9 (not used)
RenderingHints
Support
An official website of the United States government
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.