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    <Version>2.2.6</Version>
    <NumericalData>
        <ResourceID>spase://CDPP/NumericalData/AMDA/Rosetta/LAP/ros-lap-pho</ResourceID>
        <ResourceHeader>
            <ResourceName>photosaturation current (PHO)</ResourceName>
            <AlternateName>Photosaturation current derived collectively from multiple sweeps</AlternateName>
            <ReleaseDate>2016-10-15T14:08:29Z</ReleaseDate>
            <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.
            </Description>

            <Contact>       
                <PersonID>spase://CDPP/Person/Anders.Eriksson</PersonID>
                <Role>PrincipalInvestigator</Role>
            </Contact>
            <Contact>       
                <PersonID>spase://CDPP/Person/Erik.Johansson</PersonID>
                <Role>DataProducer</Role>
            </Contact>
            <InformationURL>

                <Name>RPC User Guide</Name>
                <URL>http://amda.irap.omp.eu/help/parameters/RPC_USER_GUIDE.PDF</URL>
            </InformationURL>
            <InformationURL>                

                <Name>RPC LAP User Guide</Name>
                <URL>http://amda.irap.omp.eu/help/parameters/RO-IRFU-LAP-UG.PDF</URL>
            </InformationURL>
            <InformationURL>

                <Name>RPC-LAP to Planetary Science Archive Interface Control Document</Name>

                <URL>http://amda.irap.omp.eu/help/parameters/RO-IRFU-LAP-EAICD.PDF</URL>

            </InformationURL>

            <InformationURL>
                <Name>RPC-LAP Report on cross-calibration of LAP data to measurements by other RPC instruments</Name>
                <URL>http://amda.irap.omp.eu/help/parameters/RO-IRFU-LAP-XCAL.PDF</URL>
            </InformationURL> 

        </ResourceHeader>
        <AccessInformation>
            <RepositoryID>spase://SMWG/Repository/CDPP/AMDA</RepositoryID>
            <Availability>Online</Availability>
            <AccessRights>Restricted</AccessRights>
            <AccessURL>
                <URL>http://amda.cdpp.eu</URL>
            </AccessURL>
            <Format>NetCDF</Format>
        </AccessInformation>
        <ProviderName>PSA</ProviderName>  
        <ProviderResourceName>RO-C-RPCLAP-5-xxx-DERIV2-V1.0</ProviderResourceName>
        <InstrumentID>spase://CDPP/Instrument/AMDA/Rosetta/LAP</InstrumentID>
        <MeasurementType>ThermalPlasma</MeasurementType>
        <TemporalDescription>
            <TimeSpan>
                <StartDate>2014-03-24T08:12:59Z</StartDate>
                <StopDate>2016-09-30T10:31:16Z</StopDate>
            </TimeSpan>
            <Cadence>PT60S</Cadence>
        </TemporalDescription>

        <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.           
            
        </Caveats>

        <Parameter>

            <Name>i_ph0_60m</Name>

            <ParameterKey>ros_lap_pho</ParameterKey>
            <Description>Photosaturation current derived collectively from multiple sweeps</Description>
            <Ucd/>

            <Units>A</Units>

            <RenderingHints>
                <DisplayType>TimeSeries</DisplayType>
            </RenderingHints>

            <FillValue>-1.e9</FillValue>

        </Parameter> 
        <Parameter>

            <Name>i_ph0_60m : qual</Name>

            <ParameterKey>ros_lap_pho_q</ParameterKey>
            <Description>Quality value in the range 0 (worst) to 1 (best). 
Corresponds to goodness of fit or how well the model fits the data.</Description>
            <Ucd/>
            <Units/>             
            <RenderingHints>
                <DisplayType>TimeSeries</DisplayType>
            </RenderingHints>
            <FillValue></FillValue>

        </Parameter>       

        <Parameter>
            <Name>quality flag</Name>
            <ParameterKey>ros_lap_pho_f</ParameterKey>
            <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)</Description>
            <Ucd/>
            <Units/>         
            <RenderingHints>
                <DisplayType>TimeSeries</DisplayType>
            </RenderingHints> 
             <FillValue></FillValue>
        </Parameter>            
     </NumericalData>
</Spase>