Magnetometers for space research

Ness, N. F.

doi:10.1007/bf00183028

Cited by 89 publications

(50 citation statements)

References 106 publications

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“…Measurements of planetary and interplanetary magnetic fields have been integral to space missions from their early days [76,77]. The on-board instruments designed for such missions have been able to successfully meet various inherent design challenges, including the necessity to have a very broad dynamic range for the instrument, as the magnetic fields to be measured could vary by many orders of magnitude between planetary fly-bys and the craft's sojourn in interplanetary space.…”

Section: Measuring Magnetic Fields In Spacementioning

confidence: 99%

Optical magnetometry

2007

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Some of the most sensitive methods of measuring magnetic fields utilize interactions of resonant light with atomic vapor. Recent developments in this vibrant field are improving magnetometers in many traditional areas such as measurement of geomagnetic anomalies and magnetic fields in space, and are opening the door to new ones, including, dynamical measurements of bio-magnetic fields, detection of nuclear magnetic resonance (NMR), magnetic-resonance imaging (MRI), inertialrotation sensing, magnetic microscopy with cold atoms, and tests of fundamental symmetries of Nature.

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Section: Measuring Magnetic Fields In Spacementioning

confidence: 99%

Optical magnetometry

2007

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“…It is su cient to refer the reader to Figure ref-g:schematic for a simpli ed description of their operation. For additional information the reader is referred to Ness 1970, Acuña 1974 , and Acuña and Ness, 1976a,b high energy storage system which is capable of driving the ring core sensors to peak excitations that are more than 100 times the coercive saturation force of the cores. This type of excitation eliminates from consideration many`perming' problems which h a ve been attributed to uxgate sensors in the past.…”

Section: Mag Instrument Descriptionmentioning

confidence: 99%

The Ace Magnetic Fields Experiment

Smith

L’Heureux

Ness

et al. 1998

The Advanced Composition Explorer Mission

577

515

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Abstract. The magnetic eld experiment o n A CE provides continuous measurements of the local magnetic eld in the interplanetary medium. These measurements are essential in the interpretation of simultaneous ACE observations of energetic and thermal particles distributions. The experiment consists of a pair of twin, boommounted, triaxial uxgate sensors which are located 165 inches = 4.19 meters from the center of the spacecraft on opposing solar panels. The electronics and digital processing unit DPU is mounted on the top deck of the spacecraft. The two triaxial sensors provide a balanced, fully redundant v ector instrument and permit some enhanced assessment of the spacecraft's magnetic eld. The instrument provides data for Browse and high-level products with between 3 and 6 vector s ,1 resolution for continuous coverage of the interplanetary magnetic eld. Two highresolution snapshot bu ers each hold 297 seconds of 24 vector s ,1 data while onboard Fast Fourier Transforms extend the continuous data to 12 Hz resolution. Real-time observations with 1 second resolution are provided continuously to the Space Environmental Center SEC of the National Oceanographic and Atmospheric Association NOAA for near-instantaneous, world-wide dissemination in service to space weather studies. As has been our team's tradition, high instrument reliability is obtained by the use of fully redundant systems and extremely conservative designs. We plan studies of the interplanetary medium in support of the fundamental goals of the ACE mission and cooperative studies with other ACE investigators using the combined ACE dataset as well as other ISTP spacecraft involved in the general program of Sun-Earth Connections.

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“…This experiment has been described in Ness et al (1966), Scearce et al (1968), andNess (1970). Three orthogonal components of the magnetic field were sampled at an average interval of 1.5 sec with a quantization error of + .25y, (1 y = 10-5 gauss).…”

Section: Datamentioning

confidence: 99%

Modulation of low-energy cosmic rays

Sari¹

1975

J. Geophys. Res.

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Recent theories have related the diffusion of cosmic rays in the solar wind to the power spectrum of interplanetary magnetic field fluctuations. In this study the power spectrum‐diffusion coefficient relation for low‐energy protons (T < 80 MeV) is tested directly, and the relative contribution to the scattering from directional discontinuities in the magnetic field is examined. Modulation parameters Vw/Krr, the solar wind speed divided by the radial diffusion coefficient, are calculated from Pioneer 6 magnetic field and solar wind data and are compared with simultaneous Imp 3 observations of the 20‐ to 80‐MeV proton flux. Daily variations in the 40‐ to 80‐MeV proton flux are found to respond to changes in Vw/Krr, as is predicted by a perturbation solution of the Fokker‐Planck equation once the contribution from directional discontinuities in the magnetic field is subtracted from the diffusion coefficients. This finding is interpreted to imply that a large percentage of the identified discontinuities are basically tangential. A lack of correlation between the 20‐ to 40‐MeV flux and the parameter changes is interpreted as being due to either the invalidity of the theory at lower energies or the presence of a continuous flux of high‐energy solar protons. A well‐defined time lag between changes in the 60‐ to 80‐MeV proton flux and corresponding changes in Vw/Krr is observed during a period when the interplanetary magnetic field is predominantly radial and the Imp 3‐sun‐Pioneer 6 angle is greater than 10°. This lag is consistent with the interpretation of little or no cross‐field diffusion or a perpendicular diffusion coefficient less than 3 × 1019 cm²/s.

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Magnetometers for space research

Cited by 89 publications

References 106 publications

Optical magnetometry

Optical magnetometry

The Ace Magnetic Fields Experiment

Modulation of low-energy cosmic rays

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