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The coupling between the neutral and ionized atmosphere is important to improve our understanding of the dynamics of the upper atmosphere and thus improving the prediction of space weather. The Arctic atmosphere is a natural laboratory for understanding these processes. The High-frequency Active Auroral Research Program (HAARP) facility located in Gakona Alaska hosts many scientific instruments that can be used for active experiments. An all-solid state Iron Resonance Temperature Lidar system is under development to be deployed at HAARP to enrich the capability of the HAARP facility. We present recent developments of this lidar system. Progress has been made on the development of the transmitter, and the etalon-based laser frequency monitoring system. We are modifying a commercial Nd:YAG laser to operate at 1116 nm. We have achieved broadband lasing at 1116 nm with 1mJ at 100 Hz in long-pulse mode. The 1116 nm laser will be Q-switched and injection seeded to yield narrowband high power emission. The light will then be tripled to 372 nm and serve as the lidar transmitter. Using a frequency-lock Rb laser, we demonstrate accurate monitoring of the laser’s frequency differences when locked to different Doppler free features with errors <1 MHz. This will support the measurement of temperature with this lidar.
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This content will become publicly available on December 30, 2025
Lidar Studies of the Upper Atmosphere and Near-Space Environment
The Earth’s upper atmosphere separates interplanetary space from the lower atmosphere and biosphere, absorbs harmful solar radiation, dissipates cosmic dust and energetic particles, and regulates gaseous escape and atmospheric waves, therefore protecting living things on Earth. It is difficult to observe the upper atmosphere, posing challenges to studying these processes. Advancement of lidar technologies and observations over the last decades have revolutionized the research field, significantly extended the profiling altitude ranges and capabilities, and created new potential for exploring space-atmosphere interactions. This article summarizes the principles, technologies, and major discoveries of lidar studies of the upper atmosphere and near-space environment.
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- PAR ID:
- 10585302
- Publisher / Repository:
- Elsevier
- Date Published:
- ISBN:
- 9780124095489
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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The Arctic atmosphere and subauroral region are a natural laboratory for understanding plasma-neutral and dynamical coupling in the atmosphere and geospace. During geomagnetically active periods the auroral electrojet and auroral precipitation are overhead at the High-Frequency Active Auroral Research Program (HAARP) facility in Gakona, Alaska (62°N, 145°W) and facilitate active experiments. Iron resonance lidar systems are uniquely suited for these active investigations as naturally occurring iron layers extend from the upper mesosphere to the middle thermosphere (~70-150 km). A novel lidar system has been demonstrated at the German Aerospace Center using an Nd:YAG laser that operated at a minor line at 1116 nm and was tripled to the iron resonance line at 372 nm. This prototype laser was fully solid-state without liquid dyes or flashlamps and with diode pumping. We are developing a lidar system based on this prototype system that can operate robustly at the remote location of HAARP. We will employ a diode-pumped Nd:YAG laser with second and third harmonic generation. The laser will be injection-seeded by a tunable diode laser allowing the laser to frequency scan the iron line. The laser pulse spectra will be recorded on a shot-by-shot basis using an etalon imaging system with a spectral reference. The lidar system is will operate at 372 nm, with a pulse repetition rate of 100 pps, a pulse energy of 30 mJ, and a 0.9-m diameter telescope. We present the system specifications and the expected performance of the system.more » « less
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