スピキュール諸々末松芳法（国立天文台）Solar Chromosphere
Consists of many jet-like structures (spicules), seen everywhere
over the Sun; 10^5 – 10^6 spicules at any time.
Important ingredient for mass and energy transport into theCorona.
However, its driving mechanism is still mysterious!
velocity: 20 – 100 km/sec (sound vel = 10 km/sec)height: 6000 km (hydrostatic scale height = 150 km)
width : 200 – 800 km , lifetime: 1 – 15 min

IRIS Obs. of spicules
The Mg II k (T=10K)spicules are seen as anatural upward extension of the Ca II H
(T=10K) spicules. They are consistently taller
and in several cases twice as tall. The Si IV(T=80K) spicules show a continuation of theMg II spicules and expand even farther. Manyof the Si IV spicules have a much darker
bottom third or half, with the top part of thespicule noticeably brighter. This suggests thatsuch spicules are being heated out of the Ca II
passband, and continue evolving reaching
higher layers and temperatures.

Time evolution ofspicules in IRIS
Spicules show a fast rise (>50 km/s ) andthen fading from the Ca II H ﬁltergrams. In
the IRIS ﬁltergrams, they have a similar
upward velocity but continue to rise after
they fade in Ca II, reaching heights up to20 Mm above the limb and often falling
down later in a parabolic motion. In
several cases, this rise and fall is also seenin the He II 30.4 nm (T=100K) ﬁltergrams.
This suggests that such spicules are being
heated out of the Ca II passband, andcontinue evolving reaching higher
layers and temperatures.

North Pole

Time slice map along the limb at the off-limb height of 10 arcsec. The data were taken at thenorth pole on 1 Apr 2007. Lateral motion (excursion) and oscillation get prominent as theheight goes up. The period of oscillation is 1 to 4 min, the amplitude is about 1 arcsec and5maximum lateral velocity is about 15 -25 km/sec.

Spicule lateral oscillation

Assumed wavelength

F=1/2 ρ v2 VA
ρ~10^-14g/cm^3、B~１０G → VA＝280km/sec
V=10 km/s
F＝1.4 10^5 erg/s/cm^26

Magnetic field
Coronal seismology technique also has
been applied to reduce coronal magneticfields (Kim et al. 2008) ;oscillating periods of 2-3 minutes, andtransverse displacements of 700-1000 km.
estimating magnetic field in spicules isabout 10-18 G for lower density limit andabout 43-76 G for upper density limit,
provided the wavelengh of 8 times ofmaximum spicule length.

SUVIT → B0
can derive density
EUVST → ρ
can derive B0

Parameters of transverse
oscillations

De Pontieu et al. (2007)

Transverse oscillation of spicules
v=20 km/sec
Period: 150-350 sec

Okamoto et al. (2011)
Transverse oscillation of spicules
In order to find wave propagation, oscillation withthe short period and small amplitude is used.
Are they important to understand the energy
transfer?

t
Torsional wave？

ttt

Sharpened images with a cadence of 5 sec. This series clearlyshow that the spicule of double threads (indicated by white lines) is
spinning as a whole body (spin period:
1 - 1.5 min, v～15 km/sec).
9

Possible Detection of magnetic field fluctuation in
the chromosphere(Note. Oscillations of magnetic fields, Doppler velocity and Line intesity in thephotosphere were studied in Fujimura & Tsuneta 2009).

10km/s~100km/s• Velocity amplitude δv: ~10 km/s
• Alfven velocity VA: ~ 100km/s• Magnetic fields in upper chromosphere: 10 - 100G
• δB/B = δv/VA → δB = 1 ~ 10G• In the current configuration of the spectro-polarimeter,• the amplitude can be marginally detected in He 1083 nm.
• the amplitude can be detected in Stokes-V of Ca II 854 nm.
10Energy flux and dissipation
Propagating wave, and damping
Doppler measurement at two heights
one SUVIT
the other from line in EUVST (T=100K)