Observation of long-distance radial correlation in toroidal plasma turbulence.
This Letter presents the discovery of macroscale electron temperature fluctuations with a long radial correlation length comparable to the plasma minor radius in a toroidal plasma. Their spatiotemporal structure is characterized by a low frequency of ∼1-3  kHz, ballistic radial propagation, a poloidal or toroidal mode number of m/n=1/1 (or 2/1), and an amplitude of ∼2% at maximum. Nonlinear coupling between the long-range fluctuations and the microscopic fluctuations is identified. A change of the amplitude of the long-range fluctuation is transmitted across the plasma radius at the velocity which is of the order of the drift velocity.
Research Institute for Applied Mechanics, Kyushu University, Fukuoka 816-8580, Japan.
S
S
Inagaki
T
T
Tokuzawa
K
K
Itoh
K
K
Ida
S-I
SI
Itoh
N
N
Tamura
S
S
Sakakibara
N
N
Kasuya
A
A
Fujisawa
S
S
Kubo
T
T
Shimozuma
T
T
Ido
S
S
Nishimura
H
H
Arakawa
T
T
Kobayashi
K
K
Tanaka
Y
Y
Nagayama
K
K
Kawahata
S
S
Sudo
H
H
Yamada
A
A
Komori