TY - JOUR
T1 - Jets in polar coronal holes
AU - Scullion, E.
AU - Popescu, M. D.
AU - Banerjee, D.
AU - Doyle, J. G.
AU - Erdélyi, R.
PY - 2009/10/1
Y1 - 2009/10/1
N2 - Here, we explore the nature of small-scale jet-like structures and their possible relation to explosive events and other known transient features, like spicules and macrospicules, using high-resolution spectroscopy obtained with the Solar and Heliospheric Observatory/Solar Ultraviolet Measurements of Emitted Radiation instrument. We present a highly resolved spectroscopic analysis and line parameter study of time-series data for jets occurring on-disk and off-limb in both a northern and a southern coronal hole. The analysis reveals many small-scale transients which rapidly propagate between the mid-transition region (N IV 765 line formation: 140,000 K) and the lower corona (Ne VIII 770 line formation: 630,000 K). In one example, a strong jet-like event is associated with a cool feature not present in the Ne VIII 770 line radiance or Doppler velocity maps. Another similar event is observed, but with a hot component, which could be perceived as a blinker. Our data reveal fast, repetitive plasma outflows with blueshift velocities of 145 km s-1 in the lower solar atmosphere. The data suggest a strong role for smaller jets (spicules), as a precursor to macrospicule formation, which may have a common origin with explosive events.
AB - Here, we explore the nature of small-scale jet-like structures and their possible relation to explosive events and other known transient features, like spicules and macrospicules, using high-resolution spectroscopy obtained with the Solar and Heliospheric Observatory/Solar Ultraviolet Measurements of Emitted Radiation instrument. We present a highly resolved spectroscopic analysis and line parameter study of time-series data for jets occurring on-disk and off-limb in both a northern and a southern coronal hole. The analysis reveals many small-scale transients which rapidly propagate between the mid-transition region (N IV 765 line formation: 140,000 K) and the lower corona (Ne VIII 770 line formation: 630,000 K). In one example, a strong jet-like event is associated with a cool feature not present in the Ne VIII 770 line radiance or Doppler velocity maps. Another similar event is observed, but with a hot component, which could be perceived as a blinker. Our data reveal fast, repetitive plasma outflows with blueshift velocities of 145 km s-1 in the lower solar atmosphere. The data suggest a strong role for smaller jets (spicules), as a precursor to macrospicule formation, which may have a common origin with explosive events.
KW - Line:profiles
KW - Sun:chromosphere
KW - Sun:transition region
KW - Sun:UV radiation
KW - Techniques: spectroscopic
U2 - 10.1088/0004-637X/704/2/1385
DO - 10.1088/0004-637X/704/2/1385
M3 - Article
AN - SCOPUS:70549093071
VL - 704
SP - 1385
EP - 1395
JO - Astrophysical Journal
JF - Astrophysical Journal
SN - 0004-637X
IS - 2
ER -