scholarly journals Direct Measurements of Ion Density and Conductivity in the D-region

1961 ◽  
pp. 99-102
Author(s):  
E. C. Whipple
Keyword(s):  
Ion Density ◽  
Direct Measurements ◽  
D Region

scholarly journals Electrocaloric and elastocaloric effects in soft materials

2016 ◽  
Vol 374 (2074) ◽  
pp. 20150301 ◽  
Author(s):  
Maja Trček ◽  
Marta Lavrič ◽  
George Cordoyiannis ◽  
Boštjan Zalar ◽  
Brigita Rožič ◽  
...  
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystalline ◽  
Main Chain ◽  
Soft Materials ◽  
Ion Density ◽  
Caloric Effect ◽  
Direct Measurements ◽  
Cooling Devices ◽  
Composite Mixture ◽  
Liquid Crystal Elastomers

Materials with large caloric effect have the promise of realizing solid-state refrigeration which has potential to be more efficient and environmentally friendly compared with current cooling technologies. Recently, the focus of caloric effects investigations has shifted towards soft materials. An overview of recent direct measurements of the large electrocaloric effect (ECE) in a composite mixture of a liquid crystal and nanoparticles (NPs) and large elastocaloric (eC) effect in main-chain liquid crystal elastomers is given. In mixtures of 12CB liquid crystal with functionalized CdSSe NPs, an ECE exceeding 5 K was found in the vicinity of the isotropic to smectic A phase transition. It is shown that the NPs smear the isotropic to smectic coexistence range in which a large ECE is observed due to latent heat enhancement. NPs acting as traps for ions reduce the moving-ion density and consequently the Joule heating. Direct eC measurements indicate that the significant eC response can be found in main-chain liquid crystalline elastomers, but at a fraction of the stress field in contrast to other eC materials. Both soft materials could play a significant role as active cooling elements or parts of thermal diodes in development of new cooling devices. This article is part of the themed issue ‘Taking the temperature of phase transitions in cool materials’.

scholarly journals Electron and positive ion density altitude distributions in the equatorial D-region

1972 ◽  
Vol 34 (9) ◽  
pp. 1483-1494 ◽  
Author(s):  
A.C Aikin ◽  
R.A Goldberg ◽  
Y.V Somayajulu ◽  
M.B Avadhanulu
Keyword(s):  
Ion Density ◽  
D Region ◽  
Positive Ion

Electron and ion density observations in the D-region during auroral absorption

1964 ◽  
Vol 12 (6) ◽  
pp. 543-551 ◽  
Author(s):  
M. Jespersen ◽  
O. Petersen ◽  
J. Rybner ◽  
B. Bjelland ◽  
O. Holt ◽  
...  
Keyword(s):  
Ion Density ◽  
D Region

scholarly journals The estimation of D-region electron densities from riometer data

2003 ◽  
Vol 21 (2) ◽  
pp. 603-613 ◽  
Author(s):  
J. K. Hargreaves ◽  
M. Friedrich
Keyword(s):  
Electron Density ◽  
Time Of Day ◽  
Seasonal Effect ◽  
Auroral Ionosphere ◽  
Radio Waves ◽  
Radio Science ◽  
Direct Measurements ◽  
D Region ◽  
Instruments And Techniques ◽  
The Relationship

Abstract. At high latitude the hard electron precipitation associated with auroral activity is a major source of ionization for the D-region, one consequence being the absorption of radio waves. Direct measurements of the D-region electron density are not readily available, however. This paper investigates the relationship between the electron density at altitudes between 100 and 70 km and the total radio absorption observed with a riometer, with a view to using the latter to predict the former. Tables are given of the median electron density corresponding to 1 dB absorption at 27.6 MHz for each hour of the day, and it is shown that at certain heights the estimates will be accurate to within a factor of 1.6 on 50% of the occasions. A systematic variation with time of day is probably associated with a progressive hardening of the typical electron spectrum during the morning hours. There is also evidence for a seasonal effect possibly due to seasonal variations of the mesosphere.Key words. Ionosphere (auroral ionosphere) – Radio science (ionospheric propagation; instruments and techniques)

Estimation of the electron density profile in the D region from rocket measurement of VLF signals from a ground based transmitter

1981 ◽  
Vol 64 (11) ◽  
pp. 68-74
Author(s):  
Isamu Nagano ◽  
Masayoshi Mambo ◽  
Tetsuo Fukami ◽  
Koji Namba ◽  
Iwane Kimura
Keyword(s):  
Electron Density ◽  
Density Profile ◽  
Electron Density Profile ◽  
Rocket Measurement ◽  
D Region

Rocket-borne equipment for an l.f. D region propagation experiment

1967 ◽  
Vol 114 (6) ◽  
pp. 703
Author(s):  
K. Bullough ◽  
A.J. Hall ◽  
J.E. Hall ◽  
R.W. Smith
Keyword(s):  
D Region ◽  
Propagation Experiment
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