Commit ad7a238ed66bacf987214308c9abfff2b4262d17
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small cor in LAP EFL
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NumericalData/AMDA/Rosetta/LAP/ros-lap-efl.xml
@@ -7,25 +7,26 @@ | @@ -7,25 +7,26 @@ | ||
7 | <ResourceName>e-field component (EFL)</ResourceName> | 7 | <ResourceName>e-field component (EFL)</ResourceName> |
8 | <AlternateName>Electric field component, calculated on ground by | 8 | <AlternateName>Electric field component, calculated on ground by |
9 | taking the difference between floating probe measurements on both probes and | 9 | taking the difference between floating probe measurements on both probes and |
10 | -dividing by distance, (V_P2-V_P1)/L. Positive value refers to electric field | ||
11 | -pointing in the direction from probe 1 to probe 2.</AlternateName> | 10 | +dividing by distance</AlternateName> |
12 | <ReleaseDate>2016-10-15T14:08:29Z</ReleaseDate> | 11 | <ReleaseDate>2016-10-15T14:08:29Z</ReleaseDate> |
13 | <Description> | 12 | <Description> |
14 | The two LAP probes could be used to measure the component of the electric field along their | 13 | The two LAP probes could be used to measure the component of the electric field along their |
15 | separation vector, by measuring the voltage of them, taking the difference and dividing by the | 14 | separation vector, by measuring the voltage of them, taking the difference and dividing by the |
16 | separation distance (5.0 m). Each probe could be fed by a bias current as is typically done on | 15 | separation distance (5.0 m). Each probe could be fed by a bias current as is typically done on |
17 | electric field instruments in tenuous plasmas, or be disconnected from the bias circuitry to | 16 | electric field instruments in tenuous plasmas, or be disconnected from the bias circuitry to |
18 | -ensure a good zero bias current (floating probes) as is typically done on sounding rockets. | 17 | +ensure a good zero bias current (floating probes) as is typically done on sounding rockets. |
19 | Bias currents were used in the early part of the mission, but when the comet ionosphere | 18 | Bias currents were used in the early part of the mission, but when the comet ionosphere |
20 | -developed, the floating mode was found to give much more consistent data. Only data from | 19 | +developed, the floating mode was found to give much more consistent data. Only data from |
21 | the floating mode have been used for providing E-field data, and only when both probes are | 20 | the floating mode have been used for providing E-field data, and only when both probes are |
22 | sunlit. | 21 | sunlit. |
23 | 22 | ||
23 | +Positive value refers to electric field pointing in the direction from probe 1 to probe 2. | ||
24 | + | ||
24 | The booms are not equal in length (2.24 and 1.62 m) and mounted on a big spacecraft (solar | 25 | The booms are not equal in length (2.24 and 1.62 m) and mounted on a big spacecraft (solar |
25 | panel wingspan 32 m), so one cannot expect LAP to provide a useful DC electric field estimate. | 26 | panel wingspan 32 m), so one cannot expect LAP to provide a useful DC electric field estimate. |
26 | A moving average of the E-field over 32 s is therefore subtracted from the data in the EFL files. | 27 | A moving average of the E-field over 32 s is therefore subtracted from the data in the EFL files. |
27 | -The effective bandwidth of the data therefore is about 0.03 Hz to 20 Hz, the upper | ||
28 | -limit set by the analog anti-aliasing filters. Note that the filtering may distort the lowest | 28 | +The effective bandwidth of the data therefore is about 0.03 Hz to 20 Hz, the upper |
29 | +limit set by the analog anti-aliasing filters. Note that the filtering may distort the lowest | ||
29 | frequencies. | 30 | frequencies. |
30 | 31 | ||
31 | There are no external comparison data for assessing the absolute accuracy of the LAP E-field | 32 | There are no external comparison data for assessing the absolute accuracy of the LAP E-field |