Electrical processes coupling the atmosphere and ionosphere: An overview

Rycroft, M.J.

doi:10.1016/j.jastp.2005.04.009

Cited by 64 publications

(54 citation statements)

References 88 publications

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“…The concept of a conducting layer in the D-region playing the role of the upper boundary is valid for the DC global electric circuit (e.g., Rycroft, 2006), SR (e.g., Sentman, 1995), as well for sferics and tweeks propagation (e.g., Simões et al, 2009). In the case of the DC electric circuit and to a first approximation, the ionosphere is considered equipotential above ~ 90 km.…”

Section: Boundary Conditionsmentioning

confidence: 99%

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

et al. 2011

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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 2018-05-12T18:35:14+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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Section: Boundary Conditionsmentioning

confidence: 99%

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

et al. 2011

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“…Electrical "batteries" exist below or inside electrified clouds (e.g., thunderclouds); these cause an electric current to flow up to the ionosphere. The "DC" (direct current) electric circuit is completed by downward currents flowing through the majority of the Earth's atmosphere in the "fair weather" region remote from thunderstorms, and through the rocks and oceans of the Earth's crust (Williams 2002;Harrison 2004a;Rycroft 2006;Markson 2007;Rycroft et al 2007 and references therein).…”

Section: The Global Atmospheric Electric Circuitmentioning

confidence: 99%

An Overview of Earth’s Global Electric Circuit and Atmospheric Conductivity

Rycroft¹,

et al. 2008

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The Earth's global atmospheric electric circuit depends on the upper and lower atmospheric boundaries formed by the ionosphere and the planetary surface. Thunderstorms and electrified rain clouds drive a DC current (∼1 kA) around the circuit, with the current carried by molecular cluster ions; lightning phenomena drive the AC global circuit. The Earth's near-surface conductivity ranges from 10 −7 S m −1 (for poorly conducting rocks) to 10 −2 S m −1 (for clay or wet limestone), with a mean value of 3.2 S m −1 for the ocean. Air conductivity inside a thundercloud, and in fair weather regions, depends on location (especially geomagnetic latitude), aerosol pollution and height, and varies from ∼10 −14 S m −1 just above the surface to 10 −7 S m −1 in the ionosphere at ∼80 km altitude. Ionospheric conductivity is a tensor quantity due to the geomagnetic field, and is determined by parameters such as electron density and electron-neutral particle collision frequency. In the current source regions, point discharge (coronal) currents play an important role below electrified clouds; the solar wind-magnetosphere dynamo and the unipolar dynamo due to the terrestrial rotating dipole moment also apply atmospheric potential differences. M.J. Rycroft ( ) CAESAR Consultancy,

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“…At altitudes above ∼80 km, the ionospheric plasma produced by the action of solar extreme ultraviolet and X-radiation on the tenuous upper atmosphere is also a good conductor of electricity (Schunk and Nagy 2000). Between these two conductors lies the atmosphere, which behaves like a leaky insulator (an imperfect dielectric), as discussed by Rycroft et al (2000), Williams (2002Williams ( , 2007, Harrison (2004), Rycroft (2006) and Markson (2007). The atmospheric conductivity increases with height as the ionisation produced by cosmic rays increases, from a surface value of ∼10 −14 Sm −1 (mostly from natural radioactivity emanating from the Earth) by seven orders of magnitude, to reach the large values (∼10 −7 Sm −1 ) characterising the electrically conducting ionosphere.…”

Section: Properties Of the Global Electric Circuitmentioning

confidence: 99%

“…In fair weather regions, the ionospheric potential V i , conduction current density J c and unit area columnar resistance R c are related by Ohm's Law (1978). Some more realistic models, with capacitors as well as resistors (see Rycroft 2006;Rycroft et al 2007), are introduced in Rycroft et al (2008). A simplified model of the global circuit is shown in Fig.…”

Section: Properties Of the Global Electric Circuitmentioning

confidence: 99%

Investigating Earth’s Atmospheric Electricity: a Role Model for Planetary Studies

2008

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The historical development of terrestrial atmospheric electricity is described, from its beginnings with the first observations of the potential gradient to the global electric circuit model proposed by C.T.R. Wilson in the early 20th century. The properties of the terrestrial global circuit are summarised. Concepts originally needed to develop the idea of a global circuit are identified as "central tenets", for example, the importance of radio science in establishing the conducting upper layer. The central tenets are distinguished from additional findings that merely corroborate, or are explained by, the global circuit model. Using this analysis it is possible to specify which observations are preferable for detecting global circuits in extraterrestrial atmospheres. Schumann resonances, the extremely low frequency signals generated by excitation of the surface-ionosphere cavity by electrical discharges, are identified as the most useful single measurement of electrical activity in a planetary atmosphere.

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Electrical processes coupling the atmosphere and ionosphere: An overview

Cited by 64 publications

References 88 publications

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

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

An Overview of Earth’s Global Electric Circuit and Atmospheric Conductivity

Investigating Earth’s Atmospheric Electricity: a Role Model for Planetary Studies

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