SuperDARN Polar Cap Potential

The Super Dual Auroral Radar Network (SuperDARN) is an international network of High Frequency coherent scatter radars. A map of the fields of view of the radars currently in operation can be seen in Figure 1: INAF-IAPS manages the radar pair of Dome C East (DCE) and Dome C North (DCN) located at the Concordia station, in Antarctica, whose fields of view are shaded in green in the figure. The SuperDARN concept is described in detail in [2]. A SuperDARN radar is a bistatic apparatus (i.e. the same antennae and the same electronics are used to both transmit and receive signals to/from the ionosphere), which works in the 8-20 MHz frequency range: coded sequences of radio pulses are steered through a field of view several tens degrees wide along a number of “beams” (directions), so that the whole field of view is covered in one or two minutes, depending on the operating mode. Along each beam, the pulse sequence defines from 75 to 100 range gates, from 180 km up to 3000 km from the radar site, where the radio signals encounter plasma density irregularities in the ionosphere, which cause such signals to be scattered back along the same direction. As ionospheric irregularities are dragged in the large scale convection at high latitudes, the measure of the Doppler phase shift between the emitted and backscattered waves allows to infer the velocity of the ambient plasma with respect to the sounded direction and gate.

References

https://www.sciencedirect.com/science/article/abs/pii/S136468260600263X

[1] SuperDARN Data Analysis Working Group, Thomas, E. G., Reimer, A. S., Bland, E. C., Burrell, A. G., Grocott, A., Ponomarenko, P. V., Schmidt, M. T., Shepherd, S. G., Sterne, K. T., and Walach, M.-T, SuperDARN Radar Software Toolkit (RST) 5.0 (v5.0). Zenodo (2022). https://doi.org/10.5281/zenodo.7467337

[2] Greenwald, R.A., Baker, K.B., Dudeney, J.R. et al., DARN/SuperDARN, A global view of the dynamics of high-latitude convection, Space Sci Rev, 71, 761–796 (1995). https://doi.org/10.1007/BF00751350

[3] Ruohoniemi, J.M., and K.B. Baker, Large-scale imaging of high-latitude convection with Super Dual Auroral Radar Network HF radar observations, J. Geophys. Res., Space Physics, 103, 20797-20811 (1998).https://doi.org/10.1029/98JA01288

[4] Thomas, E. G., and S. G. Shepherd, Statistical Patterns of Ionospheric Convection Derived From Mid-latitude, High-Latitude, and Polar SuperDARN HF Radar Observations, J. Geophys. Res., Space Physics, 123(4), 3196-3216 (2018). https://doi.org/10.1002/2018JA025280

[5] Baker, K. B., and S. Wing, A new coordinate system for conjugate studies at high latitudes, J. Geophys. Res., 94(A7), 9139 (1989).https://doi.org/10.1029/JA094iA07p09139 [6] Shepherd, S. G., Altitude-Adjusted Corrected Geomagnetic Coordinates: Definition and Functional Approximations, J. Geophys. Res., Space Physics, 119(9), 7501-7521 (2014). https://doi.org/10.1002/2014JA020264

Dataset summary

internal_name:	inaf_cpcp_superdarn_datacube
publisher:	INAF
alph_code:	31
id_tmp:	71
short_name:	SuperDARN CPCP
identifier:	aspis://inaf/cpcp_superdarn_datacube
dynamic:	static
size:	200MB
format:	csv
type:	timeseries
records_number:	1515672
time_start:	2015-06-21
time_stop:	2017-09-11
spatial:	IONO
messenger:	electrons,
spectral_min:	0
spectral_max:	1
spectral_units:	dimensionless
observable:	{IMF,GEOINDEX}
latest update:	2024-04-04 01:53:25

Columns specification

progr	column	units	type	description
1	time	UTC	datetime	Time representation ISO8601: YYYY-MO-DYTHR:MN:SC
2	hem		string	Flag identifying the hemisphere where data are taken for a given record. “N”=North; “S”=South
3	ndata	counts	int	Number of velocity vectors actually measured by the radars in the given time interval
4	minlat	deg	int	Low latitude limit for the convection: it is the 0 described in Section 2.
5	latpole	deg	float	Geographic latitude of the AACGM pole (North or South). It can be useful for coordinate transformations.
6	lonpole	deg	float	Geographic longitude of the AACGM pole (North or South). It can be useful for coordinate transformations.
7	radpole	Earth radii (Re=6371.2 km)	float	Distance from the centre of the Earth of the AACGM pole.
8	imfbx	nT	float	GSM* x component of the interplanetary magnetic field. Data are taken from DSCOVR spacecraft, ballistically propagated to the centre of the Earth, median filtered and averaged in the 2 minutes time intervals of the radar scans. IMF is used to select the model patterns to be added to the measured vectors in order to reconstruct convection in the whole polar cap.
9	imfby	nT	float	GSM* y component of the interplanetary magnetic field.
10	imfbz	nT	float	GSM* z component of the interplanetary magnetic field.
11	imfbt	nT	float	IMF strength. Btot = sqrt(Bx^2 + By^2 + Bz^2)
12	kpr		string	Range of geomagnetic Kp index during the given time interval. This parameter is used to select the model patterns to be added to the measured vectors in order to reconstruct convection in the whole polar cap. This field represents an information useful to be reported in the convection maps.
13	cpcp	V	float	Cross Polar Cap Potential: Maximum potential difference through the polar cap.
14	maxpot	V	float	Maximum positive value of the electric potential.
15	minpot	V	float	Minimum negative value of the electric potential.
16	l	counts	int	l-order of the harmonic expansion of the potential.
17	m	counts	int	m-order of the harmonic expansion of the potential. -l ≤ m ≤ l
18	coef	V	float	Alm coefficient of the harmonic expansion of the potential. If m<0, then the coefficient is the Blm in Eq. 2.