TY - JOUR
T1 - Density peaking by parallel flow shear driven instability
AU - Kosuga, Yusuke
AU - Itoh, Sanae I.
AU - Itoh, Kimitaka
N1 - Funding Information:
We thank stimulating discussion with Drs. S. Inagaki, T. Kobayashi, P.H. Diamond, A. Fujisawa, A. Fukuyama, T. Takizuka. This work was supported by Grants-in-Aid for Scientific Research of JSPF of Japan (21224014, 23244113, 25887041), Asada Science Foundation, Kyushu University Interdisciplinary Programs in Education and Projects in Research Development.
Publisher Copyright:
© 2015 The Japan Society of Plasma Science and Nuclear Fusion Research.
PY - 2015
Y1 - 2015
N2 - A theory to describe coupled dynamics of drift waves and D'Angelo modes is presented. The coupled dynamics is formulated by calculating fluctuation energy evolution. When drift waves dominate, turbulence production is due to release of free energy in density profile. Drift waves in turn exert Reynolds stress to drive secondary axial flows. When parallel flow shear is strong, D'Angelo modes dominate. Turbulent production occurs from release of free energy in parallel flow shear. D'Angelo modes can generate a secondary structure in density profile and can peak density profile. It is shown that when D'Angelo modes are unstable, they necessarily contribute to an inward particle flux, that compete against an outward, down-gradient flux. Net inward, upgradient particle flux can result for strong flow shear, which can lead to density peaking in plasmas. Application to laboratory and astrophysical plasmas is discussed.
AB - A theory to describe coupled dynamics of drift waves and D'Angelo modes is presented. The coupled dynamics is formulated by calculating fluctuation energy evolution. When drift waves dominate, turbulence production is due to release of free energy in density profile. Drift waves in turn exert Reynolds stress to drive secondary axial flows. When parallel flow shear is strong, D'Angelo modes dominate. Turbulent production occurs from release of free energy in parallel flow shear. D'Angelo modes can generate a secondary structure in density profile and can peak density profile. It is shown that when D'Angelo modes are unstable, they necessarily contribute to an inward particle flux, that compete against an outward, down-gradient flux. Net inward, upgradient particle flux can result for strong flow shear, which can lead to density peaking in plasmas. Application to laboratory and astrophysical plasmas is discussed.
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U2 - 10.1585/pfr.10.3401024
DO - 10.1585/pfr.10.3401024
M3 - Article
AN - SCOPUS:85034648609
SN - 1880-6821
VL - 10
JO - Plasma and Fusion Research
JF - Plasma and Fusion Research
M1 - 3401024
ER -