Rocket‐based measurements of ion velocity, neutral wind, and electric field in the collisional transition region of the auroral ionosphere

Sangalli, L.; Knudsen, D. J.; Larsen, M. F.; Zhan, Tianyu; Pfaff, R. F.; Rowland, D. E.

doi:10.1029/2008ja013757

Cited by 48 publications

(69 citation statements)

References 15 publications

(17 reference statements)

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“…Section 3 shows the observational results. These observations of lower-thermospheric wind fluctuations within pulsating aurora are, to the best of our knowledge, the first report of such an occurrence, even though an in-situ measurement of the neutral wind velocity during pulsating aurora has been previously carried out using the trimethyl aluminum (TMA) trail released during the JOULE-II sounding rocket campaign (Sangalli et al, 2009). While we have not yet identified the dominant mechanism, if any, this paper discusses effects of the electric-field perturbation associated with pulsating aurora in Sect.…”

Section: Introductionmentioning

confidence: 72%

Lower-thermospheric wind fluctuations measured with an FPI during pulsating aurora at Tromsø, Norway

et al. 2010

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Abstract.Simultaneous observations were conducted with a Fabry-Perot Interferometer (FPI) at a wavelength of 557.7 nm, an all-sky camera at a wavelength of 557.7 nm, and the European Incoherent Scatter (EISCAT) UHF radar during the Dynamics and Energetics of the Lower Thermosphere in Aurora 2 (DELTA-2) campaign in January 2009. This paper concentrated on two events during periods of pulsating aurora. The lower-thermospheric wind velocity measured with the FPI showed obvious fluctuations in both vertical and horizontal components. Of particular interest is that the location of the fluctuations was found in a darker area that appeared within the pulsating aurora. During the same time period, the EISCAT radar observed sporadic enhancements in the F-region backscatter echo power, which suggests the presence of low-energy electron (1 keV or lower) precipitation coinciding with increase in amplitude of the electromagnetic wave (at the order of 10 Hz or higher). While we have not yet identified the dominant mechanism causing the fluctuations in FPI-derived wind velocity during the pulsating aurora, the frictional heating energy dissipated by the electric-field perturbations may be responsible for the increase in ionospheric thermal energy thus modifying the local wind dynamics in the lower thermosphere.

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Section: Introductionmentioning

confidence: 72%

Lower-thermospheric wind fluctuations measured with an FPI during pulsating aurora at Tromsø, Norway

et al. 2010

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“…We validate the in situ results by comparing scale heights in κ with neutral atmosphere pressure scale heights measured by an ionization gauge. We then compare these measurements, and those of Sangalli et al [2009], with measurements from the Poker Flat Incoherent Scatter Radar (PFISR) to assess the accuracy of the radar observations of IT coupling. The instruments and observations are described in section 2.…”

Section: Introductionmentioning

confidence: 99%

High‐latitudeEregion ionosphere‐thermosphere coupling: A comparative study using in situ and incoherent scatter radar observations

et al. 2012

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[1] We present in situ and ground-based measurements of the ratio k of ion cyclotron angular frequency to ion-neutral momentum transfer collision frequency to investigate ionosphere-thermosphere (IT) coupling in the auroral E region. In situ observations were obtained by NASA sounding rocket 36.234, which was launched into the nightside E region ionosphere at 1229 UT on 19 January 2007 from Poker Flat, AK. The payload carried instrumentation to determine ion drift angle and electric field vectors. Neutral winds were measured by triangulating a chemical tracer released from rocket 41.064 launched two minutes later. k is calculated from the rotation of the ion drift angle relative to the E-cross-B drift direction in a frame co-rotating with the payload. Between the altitudes of 118 km and 130 km k increases exponentially with a scale height of 9.3 AE 0.7 km, deviating from an exponential above 130 km. k = 1 at an altitude z 0 of 119.9 AE 0.5 km. The ratio was also estimated from Poker Flat Incoherent Scatter Radar (PFISR) measurements using the rotation of ion velocity with altitude. Exponential fits to the PFISR measurements made during the flight of 41.064 yield z 0 = 115.9 AE 1.2 km and a scale height of 9.1 AE 1.0 km. Differences between in situ and ground-based measurements show that the E region atmospheric densities were structured vertically and/or horizontally on scales of 1 km to 10 km. There were no signs of ionospheric structure in ion density or ion temperature below scales of 1 km. The observations demonstrate the accuracy with which the in situ and PFISR data may be used as probes of IT coupling.

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“…Ion fluxes are amplified by using a microchannel plate and the signal is transferred to a fiber optics imaging bundle. These images are recorded with a 256 × 256 pixel charge couple device (CCD) Burchill et al (2012), Sangalli et al (2009). The inner view of the SII sensor is also illustrated in Fig.…”

Section: The Suprathermal Ion Imager: Siimentioning

confidence: 99%

“…Some studies have been devoted to analyze the rocket data and its comparison with ground based measurements. Sangalli et al (2009) analyzed rocket based measurements of the ion flow velocity, the electric and magnetic fields. From these measurements, they calculated Joule heating rates and the height integrated profiles of Pedersen and Hall conductivities for a moderately active event.…”

Section: Introductionmentioning

confidence: 99%

Impact of plasma sheath on rocket-based E-region ion measurements

Imtiaz

Burchill²,

Marchand

2014

Astrophys Space Sci

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We model the particle velocity distribution functions around the entrance window of the Suprathermal Ion Imager (SII). The SII sensor was mounted on a 1 m boom carried by the scientific payload of NASA rocket 36.234 as part of Joule II mission to investigate Joule heating in the E-region ionosphere. The rocket flew above Northern Alaska on 19 January 2007. The payload was spin-stabilized with a period of 1.6 s, giving an apparent rotation of the ion flow velocity in the frame of reference of the payload. The SII sensor is an electrostatic analyzer that measures two dimensional slices of the distribution of the kinetic energies and arrival-angles of low energy ions. The study is concerned with the interpretation of data obtained from the SII sensor. For this purpose, we numerically investigate ram velocity effects on ions velocity distributions in the vicinity of the SII sensor aperture at an altitudes of approximately 150 km. The electrostatic sheath profiles surrounding the SII sensor, boom and payload are calculated numerically with the PIC code PTetra. It is observed that the direction of the ion flow velocity modifies the plasma sheath potential profile. This in turn impacts the velocity distributions of NO + and O + 2 ions at the aperture of the particle sensor. The velocity distribution functions at the sensor aperture are cal-N. culated by using test-particle modeling. These particle distribution functions are then used to inject particles in the sensor, and calculate the fluxes on the sensor microchannel plate (MCP), from which comparisons with the measurements can be made.

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Rocket‐based measurements of ion velocity, neutral wind, and electric field in the collisional transition region of the auroral ionosphere

Cited by 48 publications

References 15 publications

Lower-thermospheric wind fluctuations measured with an FPI during pulsating aurora at Tromsø, Norway

Lower-thermospheric wind fluctuations measured with an FPI during pulsating aurora at Tromsø, Norway

High‐latitudeEregion ionosphere‐thermosphere coupling: A comparative study using in situ and incoherent scatter radar observations

Impact of plasma sheath on rocket-based E-region ion measurements

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