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Sounding of the Ion Energization Region: Resolving Ambiguities (SIERRA)
Launch date: 14 January, 2002
Launch time: 8:23:05 UT
Launch team: Principal Investigator: Paul Kintner (Cornell); Klatt, Powell (Cornell); Arnoldy, Lynch, MacDonald, Widholm (UNH); LaBelle, Samara, Harjes (Dartmouth)
Vehicle apogee: 735km (~500 sec)
Location: Poker Flat, AK (65.13¡ N, 147.48¡ W)
Instrument list: Main Payload and Two Sub Payloads. Electric Field Instruments, Plasma Wave Instruments, Magnetometers, Particle Detectors (Ions and Electrons), Thermal Electron Detectors (Cornell and UNH), HF Plasma Wave Detector (Dartmouth), GPS (Cornell)
Dartmouth College provided a high-frequency experiment (HFE) to the SIERRA sounding rocket project. The primary purpose of the HFE is to provide measurements of electron density during much of the flight. A secondary goal is to provide measurements of high-frequency wave phenomena which accompany the other auroral phenomena being investigated.
The electron density is a key parameter for both the primary and secondary goals of SIERRA. For example, the BB-ELF waves which are the primary focus of SIERRA have been previously associated with low electron densities. A comprehensive set of density measurements during occurrence of BB-ELF waves will better define the reported correlation between the waves and low-density regions.
Two secondary goals of SIERRA are determining the perpendicular scale size of solitary kinetic Alfven waves and further study of the structure of lower hybrid solitary structures (LHSS). The Alfven waves become kinetic in nature for wavelengths below the electron skin depth, a density dependent parameter. In the case of LHSS, density measurements from an HF receiver have already made an important contribution by establishing that the wave bursts occur on density gradients as predicted by theory (McAdams et al., 1998). Previous density measurements in the disturbed LHSS environment had been subject to uncertainties associated with the operation of Langmuir probes in highly inhomogeneous plasma.
The physics of auroral Langmuir, whistler, upper-hybrid and Z-mode waves is not a primary goal of SIERRA, but the HFE will provide measurements of these waves. The observational descriptions of these phenomena are still incomplete, partly because of the limited bandwidth of many of the previous high frequency wave experiments. The HFE on SIERRA will extend the observations made with PHAZE II and Auroral Turbulence II.
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