Akebono Suprathermal Mass Spectrometer (SMS)

Please also see general information of Akebono/SMS data in this page.

SMS Science Data Base (SDB)

Only fast scan data are available in the SDB. In its fast scan mode, SMS typically samples 4 major ion mass species (H⁺, He⁺, O⁺, and He⁺⁺ or O⁺⁺). In each 8-s spin period, it samples each ion species at 32 or 64 spin angles and 8 or 16 retarding potential or suprathermal energy steps.

SMS Summary Plots

Panel a:

Spin angle versus time spectrogram of thermal H⁺ ion counts

Panel b:

Spin angle versus time spectrogram of thermal He⁺ ion counts

Panel c:

Spin angle versus time spectrogram of thermal O⁺⁺ or He⁺⁺ ion counts

Panel d:

Spin angle versus time spectrogram of thermal O⁺ ion counts

Panel e:

Retarding potential steps (histograms) and minimum ram angle

Panel f:

Spin angle versus time spectrogram of suprathermal H⁺ ion counts

Panel g:

Spin angle versus time spectrogram of suprathermal O⁺ ion counts

Panel h:

Suprathermal energy steps (histograms) and minimum pitch angle

In panels a-d and g-h:

• The spin angle is defined with respect to the direction nearest to the local magnetic field, in degrees (-180 to 180). 0^o ions are parallel to (or closest to) the magnetic field, i.e. downward in the northern and upward in the southern hemispheres. +/-180^o ions are anti-parallel to (or farthest from) the magnetic field; +/-90^o ions are perpendicular to it.
• The curve denotes the spacecraft ram direction, i.e., the spin angle closest to the spacecraft velocity direction.

In panel d:

• The color of the histogram denotes the instrument entrance aperture selected for the thermal ion measurements. Red: large aperture; yellow: medium aperture; green: small aperture.
• The retarding potential, V, is in volts (0 - 25).
• The minimum ram angle, r, is in degrees (0 - 90).

In panel h:

• The suprathermal energy, E, is in volts (0 - 4000).
• The minimum pitch angle, p, is in degrees (0 - 90).

Data Reliability Flag

The horizontal line below panel h is a data quality indicator. Green: data valid; yellow: data probably reliable but caution required in data interpretation; red: data may be unreliable - consult SMS Science Team before use; white (or black): data quality unspecified.

Summary Plot, and SDB at specific date

0. Available data in each year

Please confirm which your required data is avilable or not.

1989	1990	1991	1992	1993
1994	1995	1996	1997	1998

1. Please set "Year and Month".

Year-Month: 1989 1990 1991 1992 1993 1994 1995 1996 1997 01 02 03 04 05 06 07 08 09 10 11 12

2. Please select output type

Summary Plot SDB-data