ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Space science reviews 12 (1972), S. 810-856 
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The study of Extremely-Low-Frequency (ELF) and Very-Low-Frequency (VLF) waves in space has been intensively pursued in the past decade. Search coil magnetometers, magnetic loop antennas, and electric dipole antennas have been carried on board many spacecraft. The measurements performed by these instruments have revealed a multitude of wave phenomena, whose study in turn is providing a wealth of information on the physics of the magnetospheric and ionospheric plasma. Two classes of wave phenomena are observed: whistlers and emissions. The observed whistler phenomena include: multiple hop ducted whistlers, ion-cutoff whistlers, ion cyclotron whistlers, subprotonospheric whistlers, magnetospherically reflected whistlers and walking trace whistlers. The emissions observed at high altitudes near the magnetic equator differ in many respects from those observed at low altitudes near the ionosphere. At high altitudes, inside the plasmasphere ELF hiss is the dominant emission and outside the plasmasphere chorus is the dominant emission. Also seen is a sub-LHR hiss band in the outer plasmasphere near the equator, and high pass noise and broadband noise in the outer nightside magnetosphere. At low altitude both ELF hiss and chorus are present but, here, ELF hiss is the dominant emission even outside the plasmasphere. Additional emissions, specific to low altitudes, such as VLF hiss and LHR noise are also observed. Although the observations of these phenomena by spacecraft have been complemented by many ground-based and rocket borne studies as well as by spacecraft observations of man-made signals, this paper reviews only satellite observations of signals of natural origin.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Space science reviews 13 (1972), S. 411-454 
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The study of ULF waves in space has been in progress for about 12 years. However, because of numerous observational difficulties the properties of the waves in this frequency band (10-3 to 1 Hz) are poorly known. These difficulties include the nature of satellite orbits, telemetry limitations on magnetometer frequency response and compromises between dynamic range and resolution. Despite the paucity of information, there is increasing recognition of the importance of these measurements in magnetospheric processes. A number of recent theoretical papers point out the roles such waves play in the dynamic behavior of radiation belt particles. At the present time the existing satellite observations of ULF waves suggest that the level of geomagnetic activity controls the types of waves which occur within the magnetosphere. Consequently, we consider separately quiet times, times of magnetospheric substorms and times of magnetic storms. Within each of these categories there are distinctly different wave modes distinguished by their polarization: either transverse or parallel to the ambient field. In addition, these wave phenomena occur in distinct frequency bands. In terms of the standard nomenclature of ground micropulsation studies ULF wave types observed in the magnetosphere include quiet time transverse — Pc 1, Pc 3, Pc 4, Pc 5 quiet time compressional — Pc 1 and Pi 1; substorm compressional Pi 1 and Pi 2; storm transverse — Pc 1; storm compressional Pc 4, 5. The satellite observations are not yet sufficient to determine whether the various bands identified in the ground data are equally appropriate in space.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Space science reviews 15 (1973), S. 205-266 
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The tail plays a very active and important role in substorms. Magnetic flux eroded from the dayside magnetosphere is stored here. As more and more flux is transported to the magnetotail and stored, the boundary of the tail flares more, the field strength in the tail increases, and the currents strengthen and move closer to the Earth. Further, the plasma sheet thins and the magnetic flux crossing the neutral sheet lessens. At the onset of the expansion phase, the stored magnetic flux is returned from the tail and energy is deposited in the magnetosphere and ionosphere. During the expansion phase of isolated substorms, the flaring angle and the lobe field strength decrease, the plasma sheet thickens and more magnetic flux crosses the neutral sheet. In this review, we discuss the experimental evidence for these processes and present a phenomenological or qualitative model of the substorm sequence. In this model, the flux transport is driven by the merging of the magnetospheric and interplanetary magnetic fields. During the growth phase of substorms the merging rate on the dayside magnetosphere exceeds the reconnection rate in the neutral sheet. In order to remove the oversupply of magnetic flux in the tail, a neutral point forms in the near earth portion of the tail. If the new reconnection rate exceeds the dayside merging rate, then an isolated substorm results. However, a situation can occur in which dayside merging and tail reconnection are in equilibrium. The observed polar cap electric field and its correlation with the interplanetary magnetic field is found to be in accord with open magnetospheric models.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1572-9672
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract This paper presents the consensus arrived at by the authors with respect to the contributions to the substorm expansive phase of direct energy input from the solar wind and from energy stored in the magnetotail which is released in a sometimes unpredictable manner. Two physical processes, neither of which can be ignored, are considered to be of importance in the dispensation of the energy input from the solar wind. One of these is the ‘driven process’ in which energy, supplied from the solar wind, is directly dissipated in the ionosphere with the only clearly definable delay being due to the inductance of the magnetosphere-ionosphere system. The other is the ‘loading-unloading process’ in which energy from the solar wind is first stored in the magnetotail and then is suddenly released to be deposited in the ionosphere as a consequence of external changes in the interplanetary medium or internal triggering processes. Although the driven process appears to be more dominant on a statistical basis in terms of solar wind-geomagnetic activity relationships, one or the other of the two above processes may dominate for any individual cases. Moreover, the two processes may operate simultaneously during a given phase of the substorm, e.g., the magnetotail may experience loading as the driven system increases in strength. Thus, in our approach, substorms are described in terms of physical processes which we infer to be operative in the magnetosphere and the terminology of the past (e.g., phases) is related to those inferred physical processes. The pattern of substorm development in response to changes in the interplanetary medium is presented for a canonical isolated substorm.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1 The amplitude of sudden commencements in 1910 normalized by the published amplitudes5 and plotted versus local time. In constructing this plot we assumed that the original records and tables were given in Greenwich Mean Astronomical Time which is 12 h different from the modern definition of ...
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    [s.l.] : Nature Publishing Group
    Nature 275 (1978), S. 43-45 
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Fig. 1 The magnetic field data from the geostationary spacecraft ATS6, are presented in a mean field aligned coordinate system in which Bz is measured along the mean field direction, obtained by forming a 10 min sliding average of the data. Bx is in the plane containing the Earth-satellite line and ...
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Publication Date: 2006-01-16
    Description: The prediction of fluxes of energetic particles of solar or magnetospheric origin is addressed. Topics include the prediction of the properties of the particle populations generated by magnetospheric storms and substorms, and the prediction of long term variations in the populations of magnetospheric particles.
    Keywords: SPACE RADIATION
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 415-432
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Publication Date: 2006-01-16
    Description: A schematic representation of the generation and propagation processes for energetic particles of concern in solar terrestrial predictions is given. Particle precipitation at low, mid, and high altitudes is discussed with emphasis on prediction techniques. Methods given for testing of such techniques include traditional collaborations, enhanced collaborations, simulated prediction schemes, and field tests.
    Keywords: GEOPHYSICS
    Type: NASA. Marshall Space Flight Center Solar-Terrest. Predictions Proc., Vol. 2; p 433-440
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Publication Date: 2011-08-19
    Description: The relationship between relativistic electron flux variations at 6.6 R(E) and various published indices and solar wind properties is studied. An attempt is made to characterize the temporal and dimensional relationships between solar wind or magnetic indices and electron flux enhancements. It is shown that the solar wind speed upstream of the earth's magnetosphere is correlated with large increases in the flux of highly relativistic electrons at geostationary orbit.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research (ISSN 0148-0227); 95; 15133-15
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Publication Date: 2011-08-19
    Description: The magnetic disturbance expected when the earth passed through the center of Comet Halley's tail in 1910 apparently occurred 12 hr too early. A detailed study of the records reveals that the discrepancy is due to a change in the convention for determining the start of the day. The magnetic disturbance did in fact arrive at the expected time and no unusual aberration of the solar wind need be invoked to explain the timing. The disturbance consisted of two troughs in the horizontal component of the earth's magnetic field, separated by about 14 hr, presumably associated with wakes in the solar wind momentum flux on either side of the ion tail. The disturbance was independent of latitude, indicating that the responsible current system flowed far above the earth's surface. After the comet's passage the magnetosphere was left in a mildly disturbed condition, with a weak ring current present.
    Keywords: GEOPHYSICS
    Type: Nature (ISSN 0028-0836); 333; 338-340
    Format: text
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...