Publications by authors named "J M Harlander"
Algebraic ray traces of various configurations of spatial heterodyne spectrometers are developed to derive general, approximate, formulas for resolving the power, fringe localization plane, and admissible off-axis angle for each configuration. Michelson, all-reflective, and field-widened configurations are considered separately. The derived formulas for each configuration are tested against exact numerical ray traces using optical design software and in general found to be in good agreement.
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- The NASA Ionospheric Connection Explorer (ICON) completed its two-year mission, successfully achieving and exceeding its scientific goals.
- Launched in October 2019, ICON measures plasma density in Earth's space environment, providing valuable insights into the ionosphere-thermosphere system.
- During its mission, ICON identified significant effects in the ionosphere influenced by atmospheric conditions and observed shifts in these influences as solar activity changed over time.
The design, principles of operation, calibration, and data analysis approaches of the Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) on the NASA Ionospheric Connection (ICON) satellite have been documented prior to the ICON launch. Here we update and expand on the MIGHTI wind data analysis and discuss the on-orbit instrument performance. In particular, we show typical raw data and we describe key processing steps, including the correction of a "signal-intensity dependent phase shift," which is necessitated by unexpected detector behavior.
View Article and Find Full Text PDFA quasi-2-day wave (Q2DW) event during January-February, 2020, is investigated in terms of its propagation from 96 to 250 km as a function of latitude (10°S to 30°N), its nonlinear interactions with migrating tides to produce 16 and 9.6-h secondary waves (SWs), and the plasma drift and density perturbations that it produces in the topside F-region (590-607 km) between magnetic latitudes 18°S and 18°N. This is accomplished through analysis of coincident Ionospheric Connections Explorer (ICON) measurements of neutral winds, plasma drifts and ion densities, and wind measurements from four low-latitude (±15°) specular meteor radars (SMRs).
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- * These variations are linked to "thermospheric weather," where upper-atmosphere winds react to waves from lower regions, affecting ionospheric density through wind-driven electromotive forces.
- * New findings from NASA's Ionospheric Connection Explorer provide direct evidence of the wind dynamo effect in space, highlighting a strong connection between plasma motion and thermospheric winds, which is crucial for improving predictions of the plasma environment.