Ion dynamics in the Venus ionosphere

Miller, K.L.; Whitten, R.C.

doi:10.1007/bf00177137

Cited by 64 publications

(54 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The results of the simulations suggest that several mechanisms can explain the observed intensity of the green-line in the nightside of Venus, namely the Barth, and the controversial Frederick/Kopp mechanisms. In this latter case, the variations of the O + 2 density (Bauer et al 1985;Miller & Whitten 1991) could also explain the observed intensity fluctuations. Coordinated measurements from orbiting spacecraft, and Earthbased observatories, of both O + 2 density and green-line intensity, on the nightside ionosphere of Venus, are however necessary to confirm this hypothesis.…”

Section: Discussionmentioning

confidence: 81%

Modelling the Venusian airglow

Gronoff¹,

Lilensten²,

Simon

et al. 2008

A&A

View full text Add to dashboard Cite

Context. Modelling of the Venusian ionosphere fluorescence is required, to analyse data being collected by the SPICAV instrument onboard Venus Express. Aims. We present the modelling of the production of excited states of O, CO and N 2 , which enables the computation of nightglow emissions. In the dayside, we compute several emissions, taking advantage of the small influence of resonant scattering for forbidden transitions. Methods. We compute photoionisation and photodissociation mechanisms, and the photoelectron production. We compute electron impact excitation and ionisation, through a multi-stream stationary kinetic transport code. Finally, we compute the ion recombination using a stationary chemical model. Results. We predict altitude density profiles for O( 1 S) and O( 1 D) states, and emissions corresponding to their different transitions. They are found to agree with observations. In the nightside, we discuss the different O( 1 S) excitation mechanisms as a source of green line emission. We calculate production intensities of the O( 3 S) and O( 5 S) states. For CO, we compute the Cameron bands and the Fourth Positive bands emissions. For N 2 , we compute the LBH, first and Second Positive bands. All values are compared successfully to experiments when data are available. Conclusions. For the first time, a comprehensive model is proposed to compute dayglow and nightglow emissions of the Venusian upper atmosphere. It relies on previous works with noticeable improvements, both on the transport side and on the chemical side. In the near future, a radiative-transfer model will be used to compute optically-thick lines in the dayglow, and a fluid model will be added to compute ion densities.

show abstract

Section: Discussionmentioning

confidence: 81%

Modelling the Venusian airglow

Gronoff¹,

Lilensten²,

Simon

et al. 2008

A&A

View full text Add to dashboard Cite

show abstract

“…Miller and Whitten 1991). However, this process does not accelerate the oxygen ions to greater than escape velocity; the bulk of the oxygen ions thus stay in the ionosphere, with the dayside merely supplying the nightside.…”

Section: Energy and Momentum Transfermentioning

confidence: 99%

Solar Wind Interaction and Impact on the Venus Atmosphere

et al. 2017

View full text Add to dashboard Cite

Venus has intrigued planetary scientists for decades because of its huge contrasts to Earth, in spite of its nickname of "Earth's Twin". Its invisible upper atmosphere and space environment are also part of the larger story of Venus and its evolution. In 60s to 70s, several missions (Venera and Mariner series) explored Venus-solar wind interaction regions. They identified the basic structure of the near-Venus space environment, for example, existence of the bow shock, magnetotail, ionosphere, as well as the lack of the intrinsic magnetic field. A huge leap in knowledge about the solar wind interaction with Venus was made possible by the 14-year long mission, Pioneer Venus Orbiter (PVO), launched in 1978. More recently, ESA's probe, Venus Express (VEX), was inserted into orbit in 2006, operated for 8 years.Owing to its different orbit from that of PVO, VEX made unique measurements in the polar and terminator regions, and probed the near-Venus tail for the first time. The near-tail hosts dynamic processes that lead to plasma energization. These processes in turn lead to the loss of ionospheric ions to space, slowly eroding the Venusian atmosphere. VEX carried an ion spectrometer with a moderate mass-separation capability and the observed ratio of the escaping hydrogen and oxygen ions in the wake indicates the stoichiometric loss of water from Venus. The structure and dynamics of the induced magnetosphere depends on the prevailing solar wind conditions. VEX studied the response of the magnetospheric system on different time scales. A plethora of waves was identified by the magnetometer on VEX; some of them were not previously observed by PVO. Proton cyclotron waves were seen far upstream of the bow shock, mirror mode waves were observed in magnetosheath and whistler mode waves, possibly generated by lightning discharges were frequently seen. VEX also encouraged renewed numerical modeling efforts, including fluid-type of models and particle-fluid hybrid type of models, describing the plasma interaction on scales ranging from ion gyro radius to the entire induced magnetosphere. In this review article, we review what has been found from space physics measurements around Venus (from the solar wind down to the ionopause), with a particular emphasis on updated results since the Venus Express mission. We conclude the article by a short discussion on the remaining open scientific questions and the future of this field.

show abstract

“…Also, the ionopause altitude seems to control the ionospheric O + flow into the nightside, probably affecting the escape. Figure 6 shows the flow pattern of O + ions during solar maximum (Miller and Whitten 1991). During solar minimum, however, this circuit disappears, leading to the idea that the lower location of the pressure balance boundary might disrupt ionospheric flow.…”

Section: Venusmentioning

confidence: 99%

Effects of solar variability on planetary plasma environments and habitability

Bertucci

2011

Proc. IAU

View full text Add to dashboard Cite

AbstractIntrinsic and induced planetary magnetospheres are the result of the transfer of energy and linear momentum between the solar wind and, respectively, the magnetic field and the atmospheres of solar system bodies. This transfer seems to be, however, more critical to the atmospheric evolution of unmagnetized objects such as Mars and Venus, as locally ionized planetary particles are accelerated by solar-wind induced electric fields, leading to atmospheric escape. The nature of the obstacle to the solar wind being different, intrinsic and induced magnetospheres respond differently to solar cycle changes in solar photon flux and solar wind properties. The influence of solar variability on planetary magnetospheres and its implications for atmospheric evolution based upon remote and in situ spacecraft measurements, and numerical simulations are discussed. In particular, the case of unmagnetized objects where non-thermal escape process might have played a role in their habitability conditions is considered.

show abstract

Ion dynamics in the Venus ionosphere

Cited by 64 publications

References 49 publications

Modelling the Venusian airglow

Modelling the Venusian airglow

Solar Wind Interaction and Impact on the Venus Atmosphere

Effects of solar variability on planetary plasma environments and habitability

Contact Info

Product

Resources

About