News from the Lower Ionosphere: A Review of Recent Developments

Friedrich, Martin; Rapp, Markus

doi:10.1007/s10712-009-9074-2

Cited by 72 publications

(53 citation statements)

References 145 publications

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“…Rapp and Lübken, 2004). This technique uses biased entrance grids to shield the electrode at Rapp et al (2007) and Friedrich and Rapp (2009), grey contours show MSP number densities after Hunten et al (1980), legend entries are explained in Table 1, +/-indicate the charge sign of the measured MSP.…”

Section: Charged Msp Signatures In Rocket-borne Measurementsmentioning

confidence: 99%

Meteor smoke influences on the D-region charge balance – review of recent in situ measurements and one-dimensional model results

et al. 2013

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Abstract. This work investigates the influence of meteoric smoke particles (MSP) on the charge balance in the D-region ionosphere. Both experimental in situ measurements and a one-dimensional ionospheric model reveal a clear impact of MSP on the ionospheric composition of the D-region. The study reviews rocket-borne in situ measurements of electron and positive ion density, which show a distinct deficit of electrons in comparison to positive ions between 80 and 95 km. This deficit can be explained by the ambient negatively charged MSP measured simultaneously with a Faraday cup. The influence of MSP on the D-region charge balance is addressed with a simplified ionospheric model with only six components, i.e. electrons, positive and negative ions and neutral and charged MSP (both signs). The scheme includes reactions of plasma captured by MSP and MSP photo reactions as well as the standard ionospheric processes, e.g. ionion recombination. The model shows that the capture of plasma constituents by MSP is an important process leading to scavenging of electrons. Since Faraday cup measurements are biased towards heavy MSP because of aerodynamical filtering, we have applied an estimate of this filter on the modelled MSP densities. By doing that, we find good qualitative agreement between the experimental data and our model results. In addition, the model study reveals an increase of positive ions in the presence of MSP. That is primarily caused by the reduced dissociative recombination with electrons which have been removed from the gas phase by the MSP.

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Section: Charged Msp Signatures In Rocket-borne Measurementsmentioning

confidence: 99%

Meteor smoke influences on the D-region charge balance – review of recent in situ measurements and one-dimensional model results

et al. 2013

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“…The difference in visibility is a result of differences in dust/ice particles sizes. NLCs and PMSEs appear as temperatures become lower than ∼ 155 K (Cho and Röttger, 1997;Rapp and Lübken, 2004;Friedrich and Rapp, 2009), when water ice nucleates, possibly on meteoric smoke particles (MSPs) (Hunten et al, 1980;Rapp and Thomas, 2006;Megner, 2007;Ogurtsov and Raspopov, 2011). It appears that the icy NLC/PMSE particles also act as sinks for metallic atoms injected into the upper mesosphere by evaporating meteors (Plane, 2004;Lübken and Höffner, 2004;She et al, 2006, Raizada et al, 2007.…”

Section: Introductionmentioning

confidence: 99%

A comparison of overshoot modelling with observations of polar mesospheric summer echoes at radar frequencies of 56 and 224 MHz

Havnes¹,

Pinedo²,

Hoz³

et al. 2015

Ann. Geophys.

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Abstract.We have compared radar observations of polar mesospheric summer echoes (PMSEs) modulated by artificial electron heating, at frequencies of 224 MHz (EISCAT VHF) and 56 MHz (MORRO). We have concentrated on 1 day of observation, lasting ∼ 3.8 h. The MORRO radar, with its much wider beam, observes one or more PMSE layers all the time while the VHF radar observes PMSEs in 69 % of the time. Statistically there is a clear difference between how the MORRO and the VHF radar backscatter reacts to the heater cycling (48 s heater on and 168 s heater off). While MORRO often reacts by having its backscatter level increased when the heater is switched on, as predicted by Scales and Chen (2008), the VHF radar nearly always sees the "normal" VHF overshoot behaviour with an initial rapid reduction of backscatter. However, in some heater cycles we do see a substantial recovery of the VHF backscatter after its initial reduction to levels several times above that just before the heater was switched on. For the MORRO radar a recovery during the heater-on phase is much more common. The reaction when the heater was switched off was a clear overshoot for nearly all VHF cases but less so for MORRO.A comparison of individual curves for the backscatter values as a function of time shows, at least for this particular day, that in high layers above ∼ 85 km height, both radars see a reduction of the backscatter as the heater is switched on, with little recovery during the heater-on time. These variations are well described by present models. On the other hand, the backscatter in low layers at 81-82 km can be quite different, with modest or no reduction in backscatter as the heater is switched on, followed by a strong recovery for both radars to levels several times above that of the undisturbed PMSEs. This simultaneous, nearly identical behaviour at the two very different radar frequencies is not well described by present modelling.

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“…The ice particles are observed in two phenomena at altitudes 80-95 km: noctilucent clouds (NLC) and Polar Mesosphere Summer Echoes (PMSE) (e.g. [48]). NLCs, also known as Polar Mesospheric Clouds, are optical phenomena (Figure 25) that are caused by Mie-scattering of ice particles of size above the nanometric range (e.g.…”

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Dust in the planetary system: Dust interactions in space plasmas of the solar system

Mann¹,

Meyer‐Vernet²,

Czechowski³

2014

Physics Reports

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Cosmic dust particles are small solid objects observed in the solar planetary system and in many astronomical objects like the surrounding of stars, the interstellar and even the intergalactic medium. In the solar system the dust is best observed and most often found within the region of the orbits of terrestrial planets where the dust interactions and dynamics are observed directly from spacecraft. Dust is observed in space near Earth and also enters the atmosphere of the Earth where it takes part in physical and chemical processes. Hence space offers a laboratory to study dust plasma interactions and dust dynamics. A recent example is the observation of nanodust of sizes smaller than 10 nm. We outline the theoretical considerations on which our knowledge of dust electric charges in space plasmas are founded. We discuss the dynamics of the dust particles and show how the small charged particles are accelerated by the solar wind that carries a magnetic field. Finally, as examples for the space observation of cosmic dust interactions, we describe the first detection of fast nanodust in the solar wind near Earth orbit and the first bi-static observations of PMSE, the radar echoes that are observed in the Earth ionosphere in the presence of charged dust.

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News from the Lower Ionosphere: A Review of Recent Developments

Cited by 72 publications

References 145 publications

Meteor smoke influences on the D-region charge balance – review of recent in situ measurements and one-dimensional model results

Meteor smoke influences on the D-region charge balance – review of recent in situ measurements and one-dimensional model results

A comparison of overshoot modelling with observations of polar mesospheric summer echoes at radar frequencies of 56 and 224 MHz

Dust in the planetary system: Dust interactions in space plasmas of the solar system

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