NBP1 -Table 5.5

Table 5.5: Summary of frequencies (mHz) and correlations for NBP1. See Section 5.3.4 for details.

	From:	1.00	1.33	1.67	2.00	2.33	2.67	3.00	3.33	3.67	4.00
λ	To:	1.22	1.56	1.89	2.22	2.56	2.89	3.22	3.56	3.89	4.22
Ca II K3							95	99	99		95
Hα		99,95	99		95		99			99	99,95
Mg I b2		99,99					99	95	95
Mg I b1-0.4 Å		99	99,95		99		95	99	95

Wavelengths		Correlation Coefficient	Frequency (mHz)	Timelag (Units of 45 s)	Speed (km s-1
λ1	λ2
Ca II K3	Hα	0.66 - 0.79	1.2 - 1.4	-3 - -12	<6
		0.61 - 0.72	2.3 - 2.5	4 - 6	<4
Ca II K3	Mg I b2	0.68 - 0.75	1.9 - 2.1	0
Ca II K3	Mg I b1-0.4 Å	0.57 - 0.62	1.73 - 1.93	3 - 7	5-13
Hα	Mg I b2	0.77 - 0.84	1.2 - 1.4	-3 - -7	1-7
Hα	Mg I b1-0.4 Å	0.69	4.1 - 4.3	3	7-11
Mg I b2	Mg I b1-0.4 Å	0.69 - 0.79	1.5 - 1.7	0 - 3	4-12+

The correlations between Ca II K₃ and both Mg I b₂ and Mg I b₁-0.4 Å show a possible travelling wave at ~1.9 mHz (Mg I b₂ to Mg I b₁-0.4 Å also shows a correlation at a slightly lower frequency). This corresponds with an oscillatory signal at ~1.9 mHz in Mg I b₁-0.4 Å and reduced power in Hα. There is also a peak at ~4.0 mHz in Hα, which is reduced on reaching the Ca II K₃ level. Hα to Mg I b₁-0.4 Å shows a travelling wave at ~4.1 mHz (Test 4). This all indicates a transverse wave of ~1.9 mHz coupling to a longitudinal wave at ~4.1 mHz, leaving behind a small remnant at the original frequency. This longitudinal wave then shocks, thereby explaining the lack of power in lines produced higher up in the chromosphere.

Again, there is also some weak evidence for downward- moving waves. A ~1.3 mHz correlation is found (Ca II K₃ to Hα and Hα to Mg I b₂), although among these three wavelengths an oscillatory signal at this frequency is found in Hα only. Hence the correlation is not necessarily between wave packets. Similarly the ~2.4 mHz correlation (Ca II K₃ to Hα) does not correspond to any wave-packet in either wavelength, and hence is dismissed. As in the other cases, a few frequencies exist which do not correspond to any waves. Below 1.3 mHz there is power up to the Hα level. As in NBP5 there are a lot of oscillatory power in the 2.67-3.56 mHz range which does not correspond to any travelling waves.