Polarisation effects for tweek propagation

Швец, А. В.; Hayakawa, Masashi

doi:10.1016/s1364-6826(97)00131-4

Cited by 45 publications

(51 citation statements)

References 6 publications

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“…Shvets and Hayakawa (1998) have shown that the cutoff frequency of the first harmonic falls in the range of 1.6 -2.0 kHz which compares well with the value obtained here. However, the variability in f c and hence in h and n e is larger as compared to these authors.…”

Section: Ionospheric D-region Remote Sensing Using Tweekssupporting

confidence: 91%

“…Kumar et al (1994) utilized tweeks to estimate the tweek reflection height h and propagation distance to low latitude station in the Indian sector. By analyzing tweeks up to the 8 th harmonics observed during January-April 1991, Shvets and Hayakawa (1998) estimated an increase in the electron density n e in the range 28 to 224 cm -3 at h = 81 -83 km. Ohya et al (2003) estimated the equivalent n e at the h of the night-time lower ionosphere by using the first order mode cut-off frequency.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Upper atmospheric remote sensing using ELF – VLF lightning generated tweek and whistler sferics

Kishore¹,

Deo²,

Kumar³

2016

S. Pac. J. Nat. App. Sci.

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Section: Ionospheric D-region Remote Sensing Using Tweekssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Upper atmospheric remote sensing using ELF – VLF lightning generated tweek and whistler sferics

Kishore¹,

Deo²,

Kumar³

2016

S. Pac. J. Nat. App. Sci.

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“…Tweek reflection effective height is used to investigate ionosphere dynamics during the storm and dissimilar ionospheric dynamic conditions were identified. Shvets and Hayakawa (1998) assess tweek polarization effects in the northern and southern hemispheres employing multimode analysis, finding non-reciprocity between East-West and West-East propagation and variations in wave polarization due to the geomagnetic field. From measurements of right-and left-hand ELF-VLF polarized waves, Ostapenko et al (2010) use tweek signatures to study the auroral region.…”

Section: Sferics and Tweeksmentioning

confidence: 99%

A Review of Low Frequency Electromagnetic Wave Phenomena Related to Tropospheric-Ionospheric Coupling Mechanisms

Simões¹,

Pfaff²,

Berthelier³

et al. 2011

Dynamic Coupling Between Earth’s Atmospheric and Plasma Environments

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Investigation of coupling mechanisms between the troposphere and the ionosphere requires a multidisciplinary approach involving several branches of atmospheric sciences, from meteorology, atmospheric chemistry, and fulminology to aeronomy, plasma physics, and space weather. In this work, we review low frequency electromagnetic wave propagation in the Earthionosphere cavity from a troposphere-ionosphere coupling perspective. We discuss electromagnetic wave generation, propagation, and resonance phenomena, considering atmospheric, ionospheric and magnetospheric sources, from lightning and transient luminous events at low altitude to Alfven waves and particle precipitation related to solar and magnetospheric processes. We review in situ ionospheric processes as well as surface and space weather phenomena that drive troposphere-ionosphere dynamics. Effects of aerosols, water vapor distribution, thermodynamic parameters, and cloud charge separation and electrification processes on atmospheric electricity and electromagnetic waves are reviewed. We also briefly revisit ionospheric irregularities such as spread-F and explosive spread-F, sporadic-E, traveling ionospheric disturbances, Trimpi effect, and hiss and plasma turbulence. Regarding the role of the lower boundary of the cavity, we review transient surface phenomena, including seismic activity, earthquakes, volcanic processes and dust electrification. The role of surface and https://ntrs.nasa.gov/search.jsp?R=20120011991 2019-03-25T00:54:44+00:00Z atmospheric gravity waves in ionospheric dynamics is also briefly addressed. We summarize analytical and numerical tools and techniques to model low frequency electromagnetic wave propagation and solving inverse problems and summarize in a final section a few challenging subjects that are important for a better understanding of tropospheric-ionospheric coupling mechanisms.

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“…The mean h increases as the harmonics of tweeks increases, which means that the higher harmonics of the same tweeks penetrate deeper into the nighttime lower ionosphere while reaching to the receiving station by multiple reflections (Kumar et al 2008). Tweeks are reflected at the altitudes where the plasma frequency equals the individual cut-off frequency of each harmonic, and therefore the waves with the higher harmonics are reflected at higher altitude due to the plasma frequency is higher (Shvets and Hayakawa 1998). We fit a linear function to the mean reflection Figure 3a shows that tweeks with m = 5 and 6 are reflected at the same altitude for all seasons.…”

Section: The Variations Of Reflection Height and Fundamental Frequencmentioning

confidence: 99%

Seasonal variations of nighttime D-region ionosphere in 2013 solar maximum observed from a low-latitude station

Tan¹,

Thu

et al. 2015

Earth Planet Sp

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We present the observation of tweek atmospherics with harmonics m = 1-8 during the solar maximum year, 2013, at Tay Nguyen University, Vietnam (Geog. 12.65°N, 108.02°E). The analysis of 33,690 tweeks on ten international quiet days during 2 months each season, summer (May, August), winter (February, November), and equinox (March, September), shows that tweeks occur about 51 % during summer, 22 % during winter, and 27 % during equinox. The D-region ionosphere is more sharply bounded for harmonics m = 5-6 around an altitude of 85.5 km. The environment of the D-region is more inhomogeneous during winter and equinox seasons. The mean electron density varies from 28.4-225 cm −3 , which corresponds to the harmonics m = 1-8 at the mean reflection height of 81.5-87.7 km. The results reveal that the lower reference height in our work as compared to other works is due to the higher level of solar activity. The equivalent electron density profile of the nighttime D-region ionosphere using tweek method during summer, equinox, and winter seasons shows lower values of electron density by 12-58 %, 3-67 %, and 24-76 % than those obtained using the International Reference Ionosphere (IRI-2012) model.

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Polarisation effects for tweek propagation

Cited by 45 publications

References 6 publications

Upper atmospheric remote sensing using ELF – VLF lightning generated tweek and whistler sferics

Upper atmospheric remote sensing using ELF – VLF lightning generated tweek and whistler sferics

A Review of Low Frequency Electromagnetic Wave Phenomena Related to Tropospheric-Ionospheric Coupling Mechanisms

Seasonal variations of nighttime D-region ionosphere in 2013 solar maximum observed from a low-latitude station

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