Normal and abnormal region-e ionisation

Appleton, E.V.; Naismith, Robert T.

doi:10.1088/0959-5309/52/3/311

Cited by 29 publications

(35 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…I t appears to increase slightly from sunspot minimum to sunspot maximum, but this may not be significant. The effects at high latitudes are the most marked, and there is a definite correlation with magnetic activity (Appleton et al 1937? Berkner 1939Appleton & Naismith 1940 Observation shows the behaviour or the Fx layer to be quite normal-in particular the quadratic law (3) is obeyed and the recombination coefficient is constant (Appleton & Naismith 1935).…”

Section: -2 the E Layers (Norm And Sporadic)mentioning

confidence: 98%

“…Comparison of observations at different latitudes and times of year yields the important result that a is a constant independent of the gas density in the range of E layer height (Appleton, Naismith & Ingram 1937). Several estimates have been made of the absolute value of a: Appleton (1937) gives 10-8 c.c./sec., Wilkes* (1939) 1*2 xlO -8 c.c./sec., Hulburt (1939) 2 x 10-8 c.c./sec., Bhar (1939) 4 x l0~9 c.c./sec., and Higgsf (1942) 1-OxlO-8 c.c./sec. At night ne falls to a low value of order 104/c.c.…”

Section: -2 the E Layers (Norm And Sporadic)mentioning

confidence: 99%

“…Various values of a (nocturnal) have been given: 2 x 10~9 c.c./sec. (Appleton 1937), 4 x 10~9 c.c./sec. (Wilkes 1939), and 1 x 10~9 c.c./sec.…”

Section: -2 the E Layers (Norm And Sporadic)mentioning

confidence: 99%

“…I t is located in the region of the normal layer. Appleton & Naismith (1940) (working at Slough 1934-8) determined the height as 113 km. in summer and 130 km.…”

Section: -2 the E Layers (Norm And Sporadic)mentioning

confidence: 99%

“…Several determinations have been made for the F2 layer. Appleton (1937) gives a as 8*7 x 10-u c.c./sec. for 268 a summer day, 8-1 x 10-11 c.c./sec.…”

Section: -2 the E Layers (Norm And Sporadic)mentioning

confidence: 99%

See 4 more Smart Citations

The basic reactions in the upper atmosphere. I

Bates

Massey

1946

Proc. R. Soc. Lond. A

104

View full text Add to dashboard Cite

The properties of the upper atmosphere and in particular of the ionosphere and of the nightsky emission are outlined. The fundamental processes that might be involved are discussed* Various suggestions regarding the production of the layers are considered in detail and the main difficulties indicated. The theory of the equilibrium of the layers is built up and the outstanding problem of explaining the rate of disappearance of electrons is emphasized. Current views on the origin of the night-sky light are studied critically and serious dis crepancies are shown to exist. Other possibilities are examined.1. In an earlier paper (Massey 1937) the nature of the collision processes occurring in the ionosphere was investigated in general terms with a view to understanding the observed distribution of electron and ion density in space and time. Explicit account was taken of the known stability of the negative ions of oxygen, so th at besides direct recombination of electrons and positive ions, consideration was given to attachment of electrons to O and 0 2, detachment of electrons from 0~ and 0 2, and recombination of negative and positive ions. In agreement with Martyn & Pulley (1936) it was concluded th at negative-ion phenomena are likely to play an important role in the ionosphere. From the preliminary examination of the rates of the various processes as derived from theoretical and experimental data it was suggested that the best way of regarding the situation in the E layer is to take the electrons and negative ions as in a dynamical equilibrium so that if ne, n~ are their respective densities, n~/nfi = A,where A changes only slowly with time. The apparent recombination coefficient for electrons is then given by a = ae + Aa*,where ote is the true coefficient of recombination between electrons and positive ions and that for recombination between negative and positive ions. In a second paper (Bates, Buckingham, Massey & Unwin 1939) ae was calculated by quantal methods and found to be quite inadequate to account for the observed value of a. Rough estimates of at (now thought to be too low) then suggested th at A in (2) must be taken of order 100. The difficulty of reconciling this with photo detachment effects during the daytime was not properly realized. At th at time also it appeared that a large value of A was required to explain the magnitude of the terrestrial magnetic variations, but the measurements of Appleton & Weeks (1939) on atmospheric tides now cast doubt on the validity of the theoretical treatment of this phenomenon.The basic reactions in the upper atmosphere. I

show abstract

Section: -2 the E Layers (Norm And Sporadic)mentioning

confidence: 98%

Section: -2 the E Layers (Norm And Sporadic)mentioning

confidence: 99%

“…Various values of a (nocturnal) have been given: 2 x 10~9 c.c./sec. (Appleton 1937), 4 x 10~9 c.c./sec. (Wilkes 1939), and 1 x 10~9 c.c./sec.…”

Section: -2 the E Layers (Norm And Sporadic)mentioning

confidence: 99%

“…I t is located in the region of the normal layer. Appleton & Naismith (1940) (working at Slough 1934-8) determined the height as 113 km. in summer and 130 km.…”

Section: -2 the E Layers (Norm And Sporadic)mentioning

confidence: 99%

“…Several determinations have been made for the F2 layer. Appleton (1937) gives a as 8*7 x 10-u c.c./sec. for 268 a summer day, 8-1 x 10-11 c.c./sec.…”

Section: -2 the E Layers (Norm And Sporadic)mentioning

confidence: 99%

See 3 more Smart Citations

The basic reactions in the upper atmosphere. I

Bates

Massey

1946

Proc. R. Soc. Lond. A

104

View full text Add to dashboard Cite

show abstract

The 11 Year Solar Cycle Response of the Equatorial Ionization Anomaly Observed by GPS Radio Occultation

Lin

Bui

et al. 2018

JGR Space Physics

View full text Add to dashboard Cite

We have retrieved the latitudinal and vertical structures of the 11 year solar cycle modulation on ionospheric electron density using 14 years of satellite‐based radio occultation measurements utilizing the Global Positioning System. The densities at the crests of the equatorial ionization anomaly (EIA) in the subtropics near 300 km in 2003 and 2014 (high solar activity with solar 10.7 cm flux, F10.7 ≈ 140 solar flux unit (sfu)) were 3 times higher than that in 2009 (low solar activity F10.7 ≈ 70 sfu). The higher density is attributed to the elevated solar extreme ultraviolet and geomagnetic activity during high solar activity periods. The location of the EIA crests moved ~50 km upward and ~10° poleward, because of the enhanced E × B force. The EIA in the northern hemisphere was more pronounced than that in the southern hemisphere. This interhemispheric asymmetry is consistent with the effect of enhanced transequatorial neutral wind. The above observations were reproduced qualitatively by the two benchmark runs of the Thermosphere‐Ionosphere‐Electrodynamics General Circulation Model. In addition, we have studied the impact of the 11 year solar cycle on the 27 day solar cycle response of the ionospheric electron density. Beside the expected modulation on the amplitude of the 27 day solar variation due to the 11 year solar cycle, we find that the altitude of the maximal 27 day solar response is unexpectedly ~50 km higher than that of the 11 year solar response. This is the first time that a vertical dependence of the solar responses on different time scales is reported.

show abstract

Ultra‐Violet and daylight rays in relations to the seasons and the solar cycle

Ashworth¹

1943

Quart J Royal Meteoro Soc

View full text Add to dashboard Cite

SUMMARYAccounts are given of apparatus used in the measurement of light radiation together with the results of eleven years' observations of the intensity of ultra-violet and daylight rays and their ratio. It is shown that the variation of the ratio of ultra-violet to daylight rays closely agrees with the variation of the sunspot number in the solar cycle. Observations of annual and daily inequalities of the ratio of ultra-violet t o daylight rays are also given and a comparison is made with Dr. Pettit's researches a t Mount Wilson. I.Object of the investigation and preliminary experiments An investigation was begun in the year 1927 on the variation of ultra-violet and daylight rays from day to day, from season to season, from year to year, and from one place to another, but it was not until 1931 that systematic observations were carried onA In the interval different methods of measuring these rays were tried and compared, one amongst them being the fading of methylene blue in acetone used extensively by Sir Leonard Hill, and another the liberation of iodine by the action of light on an acid solution of potassium iodide, and its determination by titration with a solution of thiosulphate of sodium.Such methods, however, a r e not altogether suitable as they do not readily distinguish between ultraviolet and daylight rays. Further the fading of methylene blue is not sensitive enough to give measurable readings in the shortest and darkest days of winter; and the potassium iodide, and other chemical methods, require laboratory operations involving time and skill which cannot always be provided in all places.I t b.ecame necessary therefore t o devise some method free from these objections, and, after much experimental work and comparison with tried methods, a n instrument was constructed, based on the photographic action of light on sensitive paper, which allowed daily records to be made with little trouble and little loss of time but of sufficient accuracy for the purpose in hand. . Description of light meters usedBriefly the instrument consists of a metal box 7 x 34 x I + in., the lid of which is filled with a sheet of a special glass which transmits ultra-violet rays in the immediate vicinity of 3,600 A. and excludes all visible rays except a weak band in the red. T h e rays which pass through the glass fall upon a step wedge, fixed upon a metal plate drilled with a hole for each step, and then impinge on a piece of sensitive paper and print upon it a graded set of spots corresponding to the steps of the wedge.The number of spots 275

show abstract

Normal and abnormal region-e ionisation

Cited by 29 publications

References 8 publications

The basic reactions in the upper atmosphere. I

The basic reactions in the upper atmosphere. I

The 11 Year Solar Cycle Response of the Equatorial Ionization Anomaly Observed by GPS Radio Occultation

Ultra‐Violet and daylight rays in relations to the seasons and the solar cycle

Contact Info

Product

Resources

About