TY - JOUR
T1 - Validation of the k-filtering technique for a signal composed of random phase plane waves and non-random coherent structures
AU - Roberts, O. W.
AU - Li, X.
AU - Jeska, L.
PY - 2014/12/23
Y1 - 2014/12/23
N2 - Recent observations of astrophysical magnetic fields have shown the
presence of fluctuations being wave-like (propagating in the plasma
frame) and those described as being structure-like (advected by the
plasma bulk velocity). Typically with single spacecraft missions it is
impossible to differentiate between these two fluctuations, due to the
inherent spatio-temporal ambiguity associated with a single point
measurement. However missions such as Cluster which contain multiple
spacecraft have allowed temporal and spatial changes to be resolved,
with techniques such as the k-filtering technique. While this technique
does not assume Taylor's hypothesis as is necessary with single
spacecraft missions, it does require weak stationarity of the time
series, and that the fluctuations can be described by a superposition of
plane waves with random phase. In this paper we test whether the method
can cope with a synthetic signal which is composed of a combination of
non-random phase coherent structures with a mean radius d and a mean
separation λ, as well as plane waves with random phase.
AB - Recent observations of astrophysical magnetic fields have shown the
presence of fluctuations being wave-like (propagating in the plasma
frame) and those described as being structure-like (advected by the
plasma bulk velocity). Typically with single spacecraft missions it is
impossible to differentiate between these two fluctuations, due to the
inherent spatio-temporal ambiguity associated with a single point
measurement. However missions such as Cluster which contain multiple
spacecraft have allowed temporal and spatial changes to be resolved,
with techniques such as the k-filtering technique. While this technique
does not assume Taylor's hypothesis as is necessary with single
spacecraft missions, it does require weak stationarity of the time
series, and that the fluctuations can be described by a superposition of
plane waves with random phase. In this paper we test whether the method
can cope with a synthetic signal which is composed of a combination of
non-random phase coherent structures with a mean radius d and a mean
separation λ, as well as plane waves with random phase.
UR - http://hdl.handle.net/2160/14178
U2 - 10.5194/gi-3-247-2014
DO - 10.5194/gi-3-247-2014
M3 - Article
SN - 2193-0856
VL - 3
SP - 435
EP - 454
JO - Geoscientific Instrumentation, Methods and Data Systems
JF - Geoscientific Instrumentation, Methods and Data Systems
IS - 2
ER -