SEET Magnetic Conjugacy
Computes the time intervals when the vehicle is magnetically conjugate with a target object. The user must specify the target object and the maximum separation angle between their respective field lines that will indicate conjugacy. The smaller the separation is made, the closer the field lines containing the vehicle and the target object must be. Valid for vehicles whose central body is earth.Available for these objects: LaunchVehicle, Missile, Satellite
Type: Time-varying data.
Availability: Reports | Graphs | Dynamic Displays | Strip Charts
Pre-data required: "<TruncObjectPath> <MaxSeparationAngle>" - e.g. "Satellite/Sat1 10.0"
Data Provider Elements
| Name | Dimension | Type | Description |
|---|---|---|---|
| Time | Date | Real Number or Text | Time. |
| Separation Angle | Angle | Real Number or Text | The centric angle between the north footprint of the field line containing the vehicle's location and the north footprint of the field line containing the target's location. The north footprint is the point of intersection of the field line with the earth's surface north of the magnetic equator. If either north footprint is not defined, then the south footprint is used. This value serves as a measure of the closeness of the vehicle's and the target's field lines - as the angle approaches zero, the field lines between the objects become equal and the objects are located on the same field line (i.e., they are magnetically conjugated). |
| Longitude Separation Angle | Angle | Real Number or Text | The longitudinal angle between the north footprint of the field line containing the vehicle's location and the north footprint of the field line containing the target's location. If either north footprint is not defined, then the south footprint is used. The longitudinal angle is measured in geomagnetic coordinates as the angle about the magnetic north pole. |
| Footprint Type | Unitless | Text | The hemisphere of the magnetic footprint: either "N" or "S". |
| Dipole L-shell parameter | Unitless | Real Number | The L value for the field line passing through the vehicle's location computed using the dipole approximation to the magnetic field. For a dipole field line, the L value corresponds to the distance, measured in earth mean radii, at the point on the field line at the magnetic equator. (For a dipole field, this point is also the furthest extent of the field line from the earth.). |
| McIlwain L-shell parameter | Unitless | Real Number or Text | A measure that indicates a particle's drift shell in the magnetic field at the vehicle's location, as defined by Carl McIlwain (J. Geophys. Res. 1961). The value is computed as a function of several magnetic invariants along a field line and thus its computation requires field line tracing. It is not strictly a constant over the entire field line. In cases where the field line is close to the dipole field line (i.e., the field line traced using only the dipole component of the magnetic field model), the value will be close to the dipole L-shell parameter. |
| McIlwain Abs(L-shell) parameter | Unitless | Real Number or Text | The absolute value of the McIlwain L-shell parameter. |
| B/Beq | Unitless | Real Number or Text | The ratio of the magnetic intensity at the vehicle's location to the minimum magnetic intensity along the field line through the vehicle's location. |
| Beq | MagneticField | Real Number or Text | The minimum magnetic intensity along the field line through the vehicle's location. The minimum value occurs at the magnetic equator, at the furthest extent of the field line from the earth. |
| Target Dipole L-shell parameter | Unitless | Real Number | The L value for the field line passing through the target's location computed using the dipole approximation to the magnetic field. |
| Target McIlwain L-shell parameter | Unitless | Real Number or Text | The L value for the field line passing through the target's location computed using McIlwain's definition. |
| Target McIlwain Abs(L-shell) parameter | Unitless | Real Number or Text | The absolute value of the McIlwain L-shell parameter of the target object. |
| Target B/Beq | Unitless | Real Number or Text | The ratio of the magnetic intensity at the target's location to the minimum magnetic intensity along the field line through the target's location. |
| Target Beq | MagneticField | Real Number or Text | The minimum magnetic intensity along the field line through the target's location. |