Photoelectron escape from the ionosphere

Nisbet, John S.

doi:10.1016/s0021-9169(68)91090-8

Cited by 87 publications

(63 citation statements)

References 15 publications

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“…This situation was first discussed by Geisler and Bowhill (1965b) and sub sequently by Nisbet (1968). It is found that some effect of thermal conduction is observed even near and below the F-region peak in smoothing out local irregu larities of temperature which might occur.…”

Section: Temperature Of the Midlatitude Ionosphere Above 140 Kmmentioning

confidence: 77%

“…In these calculations the escape of the photo-electrons is neglected so that it must be remembered that not all of the available energy is deposited where it is re leased above 300 km, although e correctly indicates the relative importance of the different scattering processes at these altitudes. Since both the production and loss rates of the photo-electrons are obtained, the number density distribution may also be calculated [Dalgarno et al (1963), Hoegy et al (1965), Nisbet (1968)], (Figure 12). At lower altitudes the structure in the energy spectrum resulting from the transition from one collision process to another can be clearly seen; this disappears at greater heights where only collisions with the ambient elec trons are important.…”

Section: Temperature Of the Midlatitude Ionosphere Above 140 Kmmentioning

confidence: 99%

“…A single collision will not always be sufficient to stop an electron moving upwards and multiple scattering must be taken into account [Geisler and Bowhill (1965b), Lejeune and Petit (1969)]. Nisbet (1968) has shown that in estimating the escape flux at various phases of the solar cycle, variations in the escape level due to changes in atmospheric temperature are important. He finds values for the particle and energy fluxes as shown in Table II.…”

Section: Temperature Of the Midlatitude Ionosphere Above 140 Kmmentioning

confidence: 99%

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Electron and ion temperatures in the ionosphere

Willmore

1970

Space Sci Rev

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Section: Temperature Of the Midlatitude Ionosphere Above 140 Kmmentioning

confidence: 77%

Section: Temperature Of the Midlatitude Ionosphere Above 140 Kmmentioning

confidence: 99%

Section: Temperature Of the Midlatitude Ionosphere Above 140 Kmmentioning

confidence: 99%

See 1 more Smart Citation

Electron and ion temperatures in the ionosphere

Willmore

1970

Space Sci Rev

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“…one needs to know the equilibrium energy spectrum of the photoelectrons (energetic electrons) that constitute the energy source of these phenomena. Several theoretical studies (Hoegy et al, 1965;Nisbet, 1968;Henry and McElroy, 1968;Dalgarno et al, 1969;Rees et al, 1969;Banks and Nagy, 1970;Nagy and Banks, 1970;Takayanagy and Itikawa, 1970;Cicerone and Bowhill, 1971a;Dalgarno and Lejeune, 1971) have progressively improved our knowledge of the energy spectrum of photoelectrons in the ionosphere. In parallel, experimental studies (Shea et al, 1968;Yngvesson and Perkins, 1968;Rao and Maier, 1970;Heikkila, 1970;Evans and Gastman, 1970;Doering et al, 1970;Cicerone and Bowhill, 1971b;Knudsen and Sharp, 1972;Galperin et al, 1972) have provided valuable data for comparison with the theoretical results.…”

Section: Introductionmentioning

confidence: 99%

Calculated photoelectron pitch angle and energy spectra

Mantas

Bowhill

1975

Planetary and Space Science

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Calculations of the steady-state photoelectron energy and angular distribution in the altitude region between 120 and 1000 km are presented.The distribution is found to be isotropic at all altitudes below 250 km, while above this altitude anisotropies in both pitch angle and energy are found. The isotropy found in the angular distribution below 250 km implies that photoelectron transport below 250 km is insignificant, while the angular anisotropy found above this altitude implies a net photoelectron current in the upward direction. The energy anisotropy above 500 km arises from the selective backscattering of the low energy photoelectron population of the upward flux component by Coulomb collisions with the ambient ions. The total photoelectron flux attains its maximum value between about 40 and 70 km above the altitude at which the photoelectron production rate is maximum. The displacement of the maximum of the equilibrium flux is attributed to an increasing (with altitude) photoelectron lifetime. Photoelectrons at altitudes above that where the flux is maximum are on the average more energetic than those below that altitude. The flux of photoelectrons escaping to the protonosphere at dawn was found to be 2.6 x 108 cm-2sec -1 , while the escaping flux at noon was found to be 1.5 x 108 cm "2 sec-1. The corresponding escaping energy fluxes are: 4.4 x 10 eV cm -2 sec -and 2.7 x 10 9 eV cm-sec -1

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“…In addition, at nonequatorial latitudes these energetic electrons can travel long distances along magnetic field lines (even to a conjugate hemisphere) before giving away their energy [Nisbet, 1968;Swartz et al, 1975 Thus, for the purpose of this study, we will use one of the methods considered in the study by Cicerone et al [1973], namely, the method developed by Nisbet [1968] and Swartz and Nisbet [1973]. This method handles …”

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confidence: 99%

Electron energy balance in the F region above Jicamarca

Aponte¹,

Swartz²,

Farley³

1999

J. Geophys. Res.

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Abstract. Incoherent scatter measurements from Jicamarca, Peru, show that current models and cross sections account quite well for the heating and cooling of F region electrons, in marked contrast to earlier similar studies at low and middle latitudes. The latter showed discrepancies of the order of a factor of 2 between the calculated energy input and loss rates. The equatorial F region ionosphere provides the simplest configuration for such studies because the horizontal magnetic field eliminates vertical photoelectron transport and thermal conduction. We based our estimates of electron heating on photoelectron energy spectra computed from recently developed solar flux models and new absorption and ionization cross sections and included the additional energy source clue to quenching of the 2D roetastable state of nitrogen. This extra source is sometimes significant. Electron and ion temperatures and densities measured with the Jicamarca incoherent scatter radar were used to complete the calculations of the heating and cooling rates. VVe present here data from 2 days, one xvith low solar activity and one with moderate activity, over the altitude range 220-325 kin. The heating/cooling rates ranged from about 500 to 6000 eV cm -3 s -1. Over this entire range the calculated heating and cooling rates differed by 10% or less when the data quality was good.

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Photoelectron escape from the ionosphere

Cited by 87 publications

References 15 publications

Electron and ion temperatures in the ionosphere

Electron and ion temperatures in the ionosphere

Calculated photoelectron pitch angle and energy spectra

Electron energy balance in the F region above Jicamarca

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