Plasma density, temperature and turbulence in the wake of the shuttle orbiter

Tribble, Alan C.; Pickett, J. S.; D’Angelo, N.; Murphy, G. B.

doi:10.1016/0032-0633(89)90054-8

Cited by 29 publications

(16 citation statements)

References 13 publications

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“…Previous work on the plasma waves associated with the space shuttle during the free-flight mission has been primarily directed toward explaining emissions generated by the FPEG experiment (fast pulse electron gun) [Gurnett et al, 1986;Bush et al, 1987;Farrell et al, 1988;Neubert et al, 1988;Reeves et al, 1988] and describing the effects of thruster firings and magnetic conjunctions . Langmuir probe data have also been used to investigate low-frequency waves (below about 40 Hz) associated with water dumps and the shuttle's orbital maneuvering system and plasma wake Pickett et al, 1989;Tribble et al, 1989, and references therein]. In this paper we will show that many of the variations in amplitude and spectral properties of the plasma waves from 31 Hz to 31 kHz observed well away from the shuttle during the freeflight mission, the so-called "mushroom" spectral features to be discussed below, can be understood in terms of the variation of the angle between the orbiter's velocity vector relative to the plasma and the magnetic field vector, the so-called Vll/V T effect.…”

mentioning

confidence: 99%

Control of plasma waves associated with the space shuttle by the angle between the orbiter's Velocity vector and the magnetic field

Cairns¹,

Gurnett²

1991

J. Geophys. Res.

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The interaction between water outgassed from the space shuttle and the ionospheric plasma leads to production of water ions by charge exchange and an active and complex plasma wave environment for the space shuttle. We show that the amplitude and spectral character of some of these waves are controlled by the angle between the magnetic field and the shuttle's velocity vector VT relative to the ionospheric plasma. When the flow is approximately perpendicular to the magnetic field (V∥/VT ∼ 0), large wave amplitudes and characteristic “mushroom” wave structures are observed, whereas more nearly parallel flows |V∥| ∼ V⊥ are characterized by low wave levels. We show that linear instability theory predicts the growth of Doppler‐shifted lower hybrid waves in the observed frequency range when driven by the ring and/or beam distributions of water ions produced by charge exchange in the vicinity of the space shuttle. Two mutually compatible interpretations for the V∥/VT effect exist. The first interpretation involves the path lengths available for growth of waves driven by pickup ions varying with the quantity V∥/VT and being limited by spatial variations in the water ion distribution. The second interpretation follows directly from the linear theory: decreasing the ring/beam speed V⊥ of the pickup ions driving the waves (increasing V∥/VT) results in smaller growth rates, with zero growth rate below some threshold value of V⊥. The linear theory shows that decreased growth lengths or growth rates should naturally produce the observed amplitude and bandwidth changes constituting the V∥/VT effect. These results have immediate implications for future shuttle missions and orbiting platforms subject to outgassing of water. If these facilities are used for ionospheric plasma studies or active experiments involving plasma waves, the plasma wave background due to pickup ions associated with the orbiter should be minimized. This requires orbits with large |V∥| ≥ V⊥; that is, orbital velocities within about 45° of the magnetic field over as much of the orbit as possible. These constraints favor more nearly polar orbits and argue strongly against equatorial orbits. Alternatively, free‐flying spacecraft situated upstream from the orbiter's water cloud should be used.

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mentioning

confidence: 99%

Control of plasma waves associated with the space shuttle by the angle between the orbiter's Velocity vector and the magnetic field

Cairns¹,

Gurnett²

1991

J. Geophys. Res.

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“…There is no evidence of large-scale turbulence in the distant wake. It should be mentioned, however, that small-scale wavelike turbulence often characterizes the boundary of the wake region 15 ; it is possible that this turbulence is similar in character to the broadband electrostatic noise discussed earlier.…”

Section: Wake Studiesmentioning

confidence: 97%

Spacelab 2 Plasma Diagnostics Package

Kŭrth

Frank

1990

Journal of Spacecraft and Rockets

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The Plasma Diagnostics Package is a small, deploy able satellite designed to study the interaction of the Space Shuttle Orbiter with the ionospheric environment as well as to be used in joint experiments with the plasma depletion and the vehicle charging and potential investigations during the Spacelab 2 mission. This paper provides a brief description of the small spacecraft, its instrumentation and operation, and the scientific objectives of the investigations. A brief summary of the scientific results obtained thus far is also presented.

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“…It was recently demonstrated that lunar polar craters develop complex surface electrical environments due to the obstruction of overflowing solar wind [4]. Self-similar models of the ambipolar plasma expansion process have been presented previously [5][6][7], and applied to the plasma wake created behind the space shuttle in the Earth's ionosphere [8], as well as the global-scale wake formed downstream of the Moon in the solar wind [10).…”

Section: The Electrical Environment Within Polar Cratersmentioning

confidence: 99%

“…An ion sonic wake structure forms behind the obstacle, not unlike that \vhich forms behind a space shuttle [8]. In the downstream re-gion where flow is obstructed, the faster moving solar wind electrons move into the void region ahead of the more massive ions, thereby creating an ambipolar electric fieJd pointing into the void region.…”

Section: Introductionmentioning

confidence: 99%