Mike Gruntman - Academia.edu (original) (raw)
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Papers by Mike Gruntman
The Astrophysical Journal, 2011
AIP Conference Proceedings, 2006
Geophysical Research Letters, 2001
The Astronautics Program of the University of Southern California (USC) offers the Master of Scie... more The Astronautics Program of the University of Southern California (USC) offers the Master of Science degree in Astronautics and Certificate in Astronautics through distance learning. The USC Distance Education Network (DEN) originally televised the classes through dedicated TV channels, with the majority of students working full time as engineers in the space industry and government research and development centers in California. Many specialized classes are being taught by adjunct faculty, prominent specialists working at the leading space companies. Today, the Internet allows us to reach students anywhere in the world through webcasting. We will describe the program's academic focus, organization, structure, available classes, and operations.
Journal of Geophysical Research: Planets, 2013
Intercept 1961: The Birth of Soviet Missile Defense, 2015
Abstract-In the past heating by elastic collisions with the solar wind protons of the interstella... more Abstract-In the past heating by elastic collisions with the solar wind protons of the interstellar helium flow into the heliosphere has been a subject ofconsideration by several authors. The approaches used in this context are critically analysed in this paper and it is shown that the concept of a continuous momentum transfer is not likely to be applicable. It is argued in contrast that large angle deflections though being rare events give the predominant contributions to the momentum transfer to the neutral helium atoms. This may have consequences for a progressed modelling of the interstellar helium distribution in the heliosphere.
Abstract-Photoionization is one of the key processes which determine the properties of fluxes of ... more Abstract-Photoionization is one of the key processes which determine the properties of fluxes of neutral atoms in interplanetary space. A new two-step channel (called indirect) of photoionization of hydrogen atoms is proposed. Hydrogen atoms are at first excited to states with principal quantum number n> 2, then decay to metastable H(2S) states, where they can be photoionized. Competing processes due to the interaction with solar wind plasma and solar radiation are considered and the photoionization rate through the proposed indirect channel is calculated. This rate depends on distance from the Sun as cc l/R4 at large distances (R> 1-2 a.u.) and as cc l/R2 at close approaches, where it is higher than the rate of direct photoionization. 1.
Operating a channel electron multiplier with a VEU-6 funnel shaped opening is studied. Different ... more Operating a channel electron multiplier with a VEU-6 funnel shaped opening is studied. Different procedures were used when recording neutral particles. The results obtained make it possible to optimally use the multiplier in actual physical studies.
This paper discusses using the one-electron pulse-height resolution to describe the properties of... more This paper discusses using the one-electron pulse-height resolution to describe the properties of open-type secondary-electron multipliers, and an example is given of the incorrect use of this. It is pointed out that the one-electron pulse-height resolution is a characteristic of the pulse-height distribution obtained on recording particles that on first collision in the secondary-electron multiplier can produce only one secondary electron each.
The outer heliosphere is inaccessible for repeated in situ investigations. One can, however, samp... more The outer heliosphere is inaccessible for repeated in situ investigations. One can, however, sample the charged-particle populations of that remote region from the inner solar system, including from Earth’s orbit, by detecting the energetic neutral atoms produced by charge exchange between the energetic ions and the ambient neutral atoms. Fluxes of energetic neutral atoms emanating from the heliospheric interface region carry information on the thermalization of the solar-wind at the termination shock and the unmodulated anomalous cosmic rays, believed to he accelerated by the termination shock. We examine the techniques for viewing the outer heliosphere in energetic neutral atoms from within.
The Astrophysical Journal, 2011
AIP Conference Proceedings, 2006
Geophysical Research Letters, 2001
The Astronautics Program of the University of Southern California (USC) offers the Master of Scie... more The Astronautics Program of the University of Southern California (USC) offers the Master of Science degree in Astronautics and Certificate in Astronautics through distance learning. The USC Distance Education Network (DEN) originally televised the classes through dedicated TV channels, with the majority of students working full time as engineers in the space industry and government research and development centers in California. Many specialized classes are being taught by adjunct faculty, prominent specialists working at the leading space companies. Today, the Internet allows us to reach students anywhere in the world through webcasting. We will describe the program's academic focus, organization, structure, available classes, and operations.
Journal of Geophysical Research: Planets, 2013
Intercept 1961: The Birth of Soviet Missile Defense, 2015
Abstract-In the past heating by elastic collisions with the solar wind protons of the interstella... more Abstract-In the past heating by elastic collisions with the solar wind protons of the interstellar helium flow into the heliosphere has been a subject ofconsideration by several authors. The approaches used in this context are critically analysed in this paper and it is shown that the concept of a continuous momentum transfer is not likely to be applicable. It is argued in contrast that large angle deflections though being rare events give the predominant contributions to the momentum transfer to the neutral helium atoms. This may have consequences for a progressed modelling of the interstellar helium distribution in the heliosphere.
Abstract-Photoionization is one of the key processes which determine the properties of fluxes of ... more Abstract-Photoionization is one of the key processes which determine the properties of fluxes of neutral atoms in interplanetary space. A new two-step channel (called indirect) of photoionization of hydrogen atoms is proposed. Hydrogen atoms are at first excited to states with principal quantum number n> 2, then decay to metastable H(2S) states, where they can be photoionized. Competing processes due to the interaction with solar wind plasma and solar radiation are considered and the photoionization rate through the proposed indirect channel is calculated. This rate depends on distance from the Sun as cc l/R4 at large distances (R> 1-2 a.u.) and as cc l/R2 at close approaches, where it is higher than the rate of direct photoionization. 1.
Operating a channel electron multiplier with a VEU-6 funnel shaped opening is studied. Different ... more Operating a channel electron multiplier with a VEU-6 funnel shaped opening is studied. Different procedures were used when recording neutral particles. The results obtained make it possible to optimally use the multiplier in actual physical studies.
This paper discusses using the one-electron pulse-height resolution to describe the properties of... more This paper discusses using the one-electron pulse-height resolution to describe the properties of open-type secondary-electron multipliers, and an example is given of the incorrect use of this. It is pointed out that the one-electron pulse-height resolution is a characteristic of the pulse-height distribution obtained on recording particles that on first collision in the secondary-electron multiplier can produce only one secondary electron each.
The outer heliosphere is inaccessible for repeated in situ investigations. One can, however, samp... more The outer heliosphere is inaccessible for repeated in situ investigations. One can, however, sample the charged-particle populations of that remote region from the inner solar system, including from Earth’s orbit, by detecting the energetic neutral atoms produced by charge exchange between the energetic ions and the ambient neutral atoms. Fluxes of energetic neutral atoms emanating from the heliospheric interface region carry information on the thermalization of the solar-wind at the termination shock and the unmodulated anomalous cosmic rays, believed to he accelerated by the termination shock. We examine the techniques for viewing the outer heliosphere in energetic neutral atoms from within.