Skip to main content

John Foster

Followers

34

Following

8

Co-authors

8

Public Views

Benjamín Reséndiz

Universidad Nacional Autónoma de México

Rice University

Patricia Ritter

Stephen Pinnock

Interests

Uploads

Papers by John Foster

Start-to-end global imaging as a sunward propagating, SAPS-associated giant undulation event

We present high-time resolution global imaging of a sunward propagating giant undulation event fr... more We present high-time resolution global imaging of a sunward propagating giant undulation event from start to finish. The event occurred on November 24, 2001 during a very disturbed storm interval. The giant undulations began to develop at around 13UT and persisted for approximately 2 hours. The sunward propagation speed was on the order of 0.6 km/s (relative to SM coordinate

Redistribution of the stormtime ionosphere and the formation of a plasmaspheric bulge

Geophysical Monograph Series, 2000

Redistribution of the Stormtime Ionosphere and the Formation of a Plasmaspheric Bulge John C. Fos... more

A 64-way VLIW/SIMD FPGA architecture and design flow

Proceedings of the 2004 11th IEEE International Conference on Electronics, Circuits and Systems, 2004. ICECS 2004., 2004

Page 1. A 64-way VLIW/SIMD FPGA Architecture and Design Flow Alex K. Jones, Raymond Hoare, Ivan S... more

Convection Plasma Drifts in the Inner Magnetosphere Associated with a Plasmaspheric Drainage Plume

We report first observations of equatorial convection signatures associated with a plasmaspheric ... more We report first observations of equatorial convection signatures associated with a plasmaspheric drainage plume using multi-satellite simultaneous observations. The Extreme Ultraviolet (EUV) sensor on board the IMAGE satellite observed a plume extending outward to L ! 2.8 near 16 - 17 magnetic local time (MLT) during the recovery phase of the 2000 Bastille Day magnetic storm. The plasmaspheric boundary was

Identifying salient usability attributes for automated telephone services

... BT Laboratories, Martlesham Heath, Ipswich ABSTRACT This paper presents experimental results ... more

MITHRAS: A brief description

Radio Science, 1984

an intensive campaign of 33 coordinated observations was carried out using the three incoherent-s... more an intensive campaign of 33 coordinated observations was carried out using the three incoherent-scatter radars capable of probing the auroral zone. During this period the groups operating the Dynamic Explorer satellites and the STARE radar made special efforts to acquire data coincident with the radar observations. The objective of these MITHRAS experiments and subsequent analysis is to further our understanding of the interactions of the magnetosphere, the ionosphere, and the thermos•here, with special emphasis on local time/universal time variations. Three experimental modes with different time resolution and spatial coverage were used to examine different aspects of these interactions. The analysis of the extensive data set involves collaboration among groups of experimenters as well as between experimenters and theoreticians.

FLUID DYNAMICS OF STELLAR JETS IN REAL TIME: THIRD EPOCH HUBBLE SPACE TELESCOPE IMAGES OF HH 1, HH 34, AND HH 47

The Astrophysical Journal, 2011

We present new, third-epoch Hubble Space Telescope Halpha and [S II] images of three Herbig-Haro ... more We present new, third-epoch Hubble Space Telescope Halpha and [S II] images of three Herbig-Haro (HH) jets (HH 1&amp;amp;amp;amp;amp;2, HH 34, and HH 47) and compare the new images with those from previous epochs. The high spatial resolution, coupled with a time series whose cadence is of order both the hydrodynamic and radiative cooling timescales of the flow, allows us

Plasmaspheric Density Structures and Dynamics: Properties Observed by the CLUSTER and IMAGE Missions

by Johan De Keyser, John Foster, Bodo Reinisch, and Johan De Keyser

Space Science Reviews, 2009

Plasmaspheric density structures have been studied since the discovery of the plasmasphere in the... more

Tomographic reconstruction of the ionosphere over North America with comparisons to ground-based radar

Radio Science, 1995

Data collection for the first ground-based ionospheric tomography campaign in North America was c... more Data collection for the first ground-based ionospheric tomography campaign in North America was conducted over a 48-hour period in mid-November 1991. The data consist of records of ionospheric total electron content (TEC) from a number of passes of the U.S. Navy Navigation Satellite System spacecraft over a chain of ground-based receiving stations. Data collection and reduction techniques are discussed; these include the determination of absolute TEC from the different phase advances induced by the ionosphere in each component of the dual-frequency spacecraft signal. The use of tomographic methods to reconstruct ionospheric electron densities over a two-dimensional (2-D) region of the Earth's ionosphere at a number of different times is demonstrated. Specifically, two distinct tomographic methods, the algebraic reconstruction technique and a maximum entropy method, are used to mathematically invert the records of TEC. The resulting 2-D contour ``maps'' of ionospheric electron density are then compared to similar maps produced by the Millstone Hill incoherent backscatter radar facility located at Westford, Massachusetts. Both qualitative and quantitative measures of agreement among the different reconstructions and the radar maps are presented. The behavior of the ionosphere over the course of the experiment is discussed.

Providing Animated Characters with Designated Personality Profiles

Aspect angle variations in intensity, phase velocity, and altitude for high-latitude 34-cm E region irregularities

Journal of Geophysical Research, 1992

ABSTRACT

Dual-mode E region plasma wave observations from Millstone Hill

Journal of Geophysical Research, 1993

The authors report on observations of E region plasma wave phenomena using the Millstone Hill rad... more The authors report on observations of E region plasma wave phenomena using the Millstone Hill radar installation. Millstone Hill has a dual-mode capability, namely it can receive coherent and incoherent backscatter signals with high sensitivity. The authors look at 34 cm radiation in this study, which is in the wavelength range of modified two-stream instabilities (or Farley-Buneman instabilities), which are thought to be one of the main instability sources in the lower E region. The experiment was to compare spectral properties of the unstable auroral E region with almost simultaneous line-of-sight electric field components of the E [times] B F region drift. The spectral properties looked at include peak amplitude, phase velocity, and spectral width. Conclusions include the following points. The irregularities observed tend to be field aligned. The 34 cm waves show velocities close to the ion-acoustic velocity, and their spectral signatures support the two-stream instability as a source. The waves are seen at large angles with respect to the plasma flow. Evidence was seen for the presence of a neutral wind blowing east to west during one event. A wide broadband coherent component was observed superimposed on the primary and secondary waves.

Observations from Millstone Hill during the geomagnetic disturbances of March and April 1990

Journal of Geophysical Research, 1992

... About an hour later, ion outflow was observed just equatorward of Millstone. ... Citation: Bu... more

Global measures of ionospheric electrodynamic activity inferred from combined incoherent scatter radar and ground magnetometer observations

Journal of Geophysical Research, 1990

An analysis of several global measures of high-latitude ionospheric electrodynamic activity is un... more An analysis of several global measures of high-latitude ionospheric electrodynamic activity is undertaken on the basis of results obtained from the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) procedure applied to incoherent scatter radar and ground magnetometer observations for January 18-19, 1984. Different global measures of electric potentials, currents, resistances, and energy transfer from the magnetosphere show temporal variations that are

Long-duration penetration of the interplanetary electric field to the low-latitude ionosphere during the main phase of magnetic storms

Journal of Geophysical Research, 2005

1] It is well known that the interplanetary electric field can penetrate to the low-latitude iono... more 1] It is well known that the interplanetary electric field can penetrate to the low-latitude ionosphere. It is generally believed that the penetration of electric fields can last only for $30 min because of the shielding effect in the ring current. In this paper we present the observations of the dayside ionospheric electric field enhancements at middle and low latitudes in association with reorientations of the interplanetary magnetic field (IMF). In six cases, the eastward electric field in the dayside equatorial ionosphere, measured by the Jicamarca incoherent scatter radar, was enhanced for 2-3 hours after the IMF turned southward and remained continuously southward. In one case the eastward electric field in the dayside midlatitude ionosphere, measured by the Millstone Hill incoherent scatter radar, was continuously enhanced for $10 hours during southward IMF. Since Millstone Hill is close to the equatorward boundary of the auroral zone during magnetic storms, the penetration electric field there may be different from that at the equatorial ionosphere. The most striking feature of the measurements is that the enhancements of the ionospheric electric field can last for many hours without significant decay. The electric field enhancements in the middle-and low-latitude ionosphere are closely related to magnetic activity and occur during the main phase of magnetic storms. The observations show that the interplanetary electric field can continuously penetrate to the low-latitude ionosphere without shielding for many hours as long as the strengthening of the magnetic activity is going on under storm conditions. Citation: Huang, C.-S., J. C. Foster, and M. C. Kelley (2005), Long-duration penetration of the interplanetary electric field to the low-latitude ionosphere during the main phase of magnetic storms,

Start-to-end global imaging of a sunward propagating, SAPS-associated giant undulation event

Journal of Geophysical Research, 2010

1] We present high time resolution global imaging of a sunward propagating giant undulation event... more 1] We present high time resolution global imaging of a sunward propagating giant undulation event from start to finish. The event occurred on 24 November 2001 during a very disturbed storm interval. The giant undulations began to develop at around 1345 UTC and persisted for approximately 2 h. The sunward propagation speed was on the order of 0.6 km/s (relative to magnetic latitude-magnetic local time coordinate system). The undulations had a wavelength of ∼718 km and amplitudes of ∼890 km and produced ULF pulsations on the ground with a period of ∼1108 s. We show (1) that the undulations were associated with subauroral polarization stream (SAPS) flows that were caused by the proton plasma sheet penetrating substantially farther earthward than the electron plasma sheet on the duskside and (2) that they may have been related to the arrival on the duskside of a substorm-associated westward traveling surge-like structure. The observations appear to be consistent with the development of a shear flow and/or ballooning type of instability at the plasmapause driven by intense SAPS-associated shear flows.

Magnetospheric substorms—definition and signatures

by John Foster and R. McPherron

Journal of Geophysical Research, 1980

For many years, researchers have utilized definitions of the substorm phenomenon that are not con... more For many years, researchers have utilized definitions of the substorm phenomenon that are not consistent among one another, and this has created great difficulties in comparing the results reported in the literature by the various researchers. In August 1978, nine magnetospheric physicists active in the field of substorm research met in Victoria, British Columbia, Canada, to attempt to reach a consensus on an acceptable definition for a magnetospheric substorm. This paper reports the agreements reached at the Victoria workshop and presents an operational definition of the magnetospheric substorm and a critique of the various signatures by which researchers can identify the time sequence and spatial extent of the substorm.

High-latitude convection: Comparison of a simple model with incoherent scatter observations

Journal of Geophysical Research, 1980

We have compared a simple model of predictions of plasma flow patterns with plasma convection at ... more We have compared a simple model of predictions of plasma flow patterns with plasma convection at high latitudes with data observations by the incoherent scatter radar obtained from simultaneous measurements made by technique. Of particular interest are the incoherent scatter facilities at Chatanika, differences of plasma flow predicted by the model Alaska and Millstone Hill, Massachusetts in June at different

Multiradar observations of the polar tongue of ionization

Journal of Geophysical Research, 2005

1] We present a global view of large-scale ionospheric disturbances during the main phase of a ma... more 1] We present a global view of large-scale ionospheric disturbances during the main phase of a major geomagnetic storm. We find that the low-latitude, auroral, and polar latitude regions are coupled by processes that redistribute thermal plasma throughout the system. For the large geomagnetic storm on 20 November 2003, we examine data from the high-latitude incoherent scatter radars at Millstone Hill, Sondrestrom, and EISCAT Tromso, with SuperDARN HF radar observations of the high-latitude convection pattern and DMSP observations of in situ plasma parameters in the topside ionosphere. We combine these with north polar maps of stormtime plumes of enhanced total electron content (TEC) derived from a network of GPS receivers. The polar tongue of ionization (TOI) is seen to be a continuous stream of dense cold plasma entrained in the global convection pattern. The dayside source of the TOI is the plume of storm enhanced density (SED) transported from low latitudes in the postnoon sector by the subauroral disturbance electric field. Convection carries this material through the dayside cusp and across the polar cap to the nightside where the auroral F region is significantly enhanced by the SED material. The three incoherent scatter radars provided full altitude profiles of plasma density, temperatures, and vertical velocity as the TOI plume crossed their different positions, under the cusp, in the center of the polar cap, and at the midnight oval/polar cap boundary. Greatly elevated F peak density (>1.5E12 m À3 ) and low electron and ion temperatures ($2500 K at the F peak altitude) characterize the SED/TOI plasma observed at all points along its high-latitude trajectory. For this event, SED/TOI F region TEC (150-1000 km) was $50 TECu both in the cusp and in the center of the polar cap. Large, upward directed fluxes of O+ (>1.E14 m À2 s À1 ) were observed in the topside ionosphere from the SED/TOI plume within the cusp.

Significant depletions of the ionospheric plasma density at middle latitudes: A possible signature of equatorial spread F bubbles near the plasmapause

Journal of Geophysical Research, 2007

Plasma density irregularities in the equatorial F region ionosphere are generally called equatori... more Plasma density irregularities in the equatorial F region ionosphere are generally called equatorial spread F (ESF). Large-scale plasma bubbles associated with ESF processes are generated in the bottomside F region and penetrate the F peak to the topside F region. It is still not fully understood how high ESF bubbles can reach. In this paper, we present the measurements of

Start-to-end global imaging as a sunward propagating, SAPS-associated giant undulation event

We present high-time resolution global imaging of a sunward propagating giant undulation event fr... more We present high-time resolution global imaging of a sunward propagating giant undulation event from start to finish. The event occurred on November 24, 2001 during a very disturbed storm interval. The giant undulations began to develop at around 13UT and persisted for approximately 2 hours. The sunward propagation speed was on the order of 0.6 km/s (relative to SM coordinate

Redistribution of the stormtime ionosphere and the formation of a plasmaspheric bulge

Geophysical Monograph Series, 2000

Redistribution of the Stormtime Ionosphere and the Formation of a Plasmaspheric Bulge John C. Fos... more

A 64-way VLIW/SIMD FPGA architecture and design flow

Proceedings of the 2004 11th IEEE International Conference on Electronics, Circuits and Systems, 2004. ICECS 2004., 2004

Page 1. A 64-way VLIW/SIMD FPGA Architecture and Design Flow Alex K. Jones, Raymond Hoare, Ivan S... more

Convection Plasma Drifts in the Inner Magnetosphere Associated with a Plasmaspheric Drainage Plume

We report first observations of equatorial convection signatures associated with a plasmaspheric ... more We report first observations of equatorial convection signatures associated with a plasmaspheric drainage plume using multi-satellite simultaneous observations. The Extreme Ultraviolet (EUV) sensor on board the IMAGE satellite observed a plume extending outward to L ! 2.8 near 16 - 17 magnetic local time (MLT) during the recovery phase of the 2000 Bastille Day magnetic storm. The plasmaspheric boundary was

Identifying salient usability attributes for automated telephone services

... BT Laboratories, Martlesham Heath, Ipswich ABSTRACT This paper presents experimental results ... more

MITHRAS: A brief description

Radio Science, 1984

an intensive campaign of 33 coordinated observations was carried out using the three incoherent-s... more an intensive campaign of 33 coordinated observations was carried out using the three incoherent-scatter radars capable of probing the auroral zone. During this period the groups operating the Dynamic Explorer satellites and the STARE radar made special efforts to acquire data coincident with the radar observations. The objective of these MITHRAS experiments and subsequent analysis is to further our understanding of the interactions of the magnetosphere, the ionosphere, and the thermos•here, with special emphasis on local time/universal time variations. Three experimental modes with different time resolution and spatial coverage were used to examine different aspects of these interactions. The analysis of the extensive data set involves collaboration among groups of experimenters as well as between experimenters and theoreticians.

FLUID DYNAMICS OF STELLAR JETS IN REAL TIME: THIRD EPOCH HUBBLE SPACE TELESCOPE IMAGES OF HH 1, HH 34, AND HH 47

The Astrophysical Journal, 2011

We present new, third-epoch Hubble Space Telescope Halpha and [S II] images of three Herbig-Haro ... more We present new, third-epoch Hubble Space Telescope Halpha and [S II] images of three Herbig-Haro (HH) jets (HH 1&amp;amp;amp;amp;amp;2, HH 34, and HH 47) and compare the new images with those from previous epochs. The high spatial resolution, coupled with a time series whose cadence is of order both the hydrodynamic and radiative cooling timescales of the flow, allows us

Plasmaspheric Density Structures and Dynamics: Properties Observed by the CLUSTER and IMAGE Missions

by Johan De Keyser, John Foster, Bodo Reinisch, and Johan De Keyser

Space Science Reviews, 2009

Plasmaspheric density structures have been studied since the discovery of the plasmasphere in the... more

Tomographic reconstruction of the ionosphere over North America with comparisons to ground-based radar

Radio Science, 1995

Data collection for the first ground-based ionospheric tomography campaign in North America was c... more Data collection for the first ground-based ionospheric tomography campaign in North America was conducted over a 48-hour period in mid-November 1991. The data consist of records of ionospheric total electron content (TEC) from a number of passes of the U.S. Navy Navigation Satellite System spacecraft over a chain of ground-based receiving stations. Data collection and reduction techniques are discussed; these include the determination of absolute TEC from the different phase advances induced by the ionosphere in each component of the dual-frequency spacecraft signal. The use of tomographic methods to reconstruct ionospheric electron densities over a two-dimensional (2-D) region of the Earth's ionosphere at a number of different times is demonstrated. Specifically, two distinct tomographic methods, the algebraic reconstruction technique and a maximum entropy method, are used to mathematically invert the records of TEC. The resulting 2-D contour ``maps'' of ionospheric electron density are then compared to similar maps produced by the Millstone Hill incoherent backscatter radar facility located at Westford, Massachusetts. Both qualitative and quantitative measures of agreement among the different reconstructions and the radar maps are presented. The behavior of the ionosphere over the course of the experiment is discussed.

Providing Animated Characters with Designated Personality Profiles

Aspect angle variations in intensity, phase velocity, and altitude for high-latitude 34-cm E region irregularities

Journal of Geophysical Research, 1992

ABSTRACT

Dual-mode E region plasma wave observations from Millstone Hill

Journal of Geophysical Research, 1993

The authors report on observations of E region plasma wave phenomena using the Millstone Hill rad... more The authors report on observations of E region plasma wave phenomena using the Millstone Hill radar installation. Millstone Hill has a dual-mode capability, namely it can receive coherent and incoherent backscatter signals with high sensitivity. The authors look at 34 cm radiation in this study, which is in the wavelength range of modified two-stream instabilities (or Farley-Buneman instabilities), which are thought to be one of the main instability sources in the lower E region. The experiment was to compare spectral properties of the unstable auroral E region with almost simultaneous line-of-sight electric field components of the E [times] B F region drift. The spectral properties looked at include peak amplitude, phase velocity, and spectral width. Conclusions include the following points. The irregularities observed tend to be field aligned. The 34 cm waves show velocities close to the ion-acoustic velocity, and their spectral signatures support the two-stream instability as a source. The waves are seen at large angles with respect to the plasma flow. Evidence was seen for the presence of a neutral wind blowing east to west during one event. A wide broadband coherent component was observed superimposed on the primary and secondary waves.

Observations from Millstone Hill during the geomagnetic disturbances of March and April 1990

Journal of Geophysical Research, 1992

... About an hour later, ion outflow was observed just equatorward of Millstone. ... Citation: Bu... more

Global measures of ionospheric electrodynamic activity inferred from combined incoherent scatter radar and ground magnetometer observations

Journal of Geophysical Research, 1990

An analysis of several global measures of high-latitude ionospheric electrodynamic activity is un... more An analysis of several global measures of high-latitude ionospheric electrodynamic activity is undertaken on the basis of results obtained from the Assimilative Mapping of Ionospheric Electrodynamics (AMIE) procedure applied to incoherent scatter radar and ground magnetometer observations for January 18-19, 1984. Different global measures of electric potentials, currents, resistances, and energy transfer from the magnetosphere show temporal variations that are

Long-duration penetration of the interplanetary electric field to the low-latitude ionosphere during the main phase of magnetic storms

Journal of Geophysical Research, 2005

1] It is well known that the interplanetary electric field can penetrate to the low-latitude iono... more 1] It is well known that the interplanetary electric field can penetrate to the low-latitude ionosphere. It is generally believed that the penetration of electric fields can last only for $30 min because of the shielding effect in the ring current. In this paper we present the observations of the dayside ionospheric electric field enhancements at middle and low latitudes in association with reorientations of the interplanetary magnetic field (IMF). In six cases, the eastward electric field in the dayside equatorial ionosphere, measured by the Jicamarca incoherent scatter radar, was enhanced for 2-3 hours after the IMF turned southward and remained continuously southward. In one case the eastward electric field in the dayside midlatitude ionosphere, measured by the Millstone Hill incoherent scatter radar, was continuously enhanced for $10 hours during southward IMF. Since Millstone Hill is close to the equatorward boundary of the auroral zone during magnetic storms, the penetration electric field there may be different from that at the equatorial ionosphere. The most striking feature of the measurements is that the enhancements of the ionospheric electric field can last for many hours without significant decay. The electric field enhancements in the middle-and low-latitude ionosphere are closely related to magnetic activity and occur during the main phase of magnetic storms. The observations show that the interplanetary electric field can continuously penetrate to the low-latitude ionosphere without shielding for many hours as long as the strengthening of the magnetic activity is going on under storm conditions. Citation: Huang, C.-S., J. C. Foster, and M. C. Kelley (2005), Long-duration penetration of the interplanetary electric field to the low-latitude ionosphere during the main phase of magnetic storms,

Start-to-end global imaging of a sunward propagating, SAPS-associated giant undulation event

Journal of Geophysical Research, 2010

1] We present high time resolution global imaging of a sunward propagating giant undulation event... more 1] We present high time resolution global imaging of a sunward propagating giant undulation event from start to finish. The event occurred on 24 November 2001 during a very disturbed storm interval. The giant undulations began to develop at around 1345 UTC and persisted for approximately 2 h. The sunward propagation speed was on the order of 0.6 km/s (relative to magnetic latitude-magnetic local time coordinate system). The undulations had a wavelength of ∼718 km and amplitudes of ∼890 km and produced ULF pulsations on the ground with a period of ∼1108 s. We show (1) that the undulations were associated with subauroral polarization stream (SAPS) flows that were caused by the proton plasma sheet penetrating substantially farther earthward than the electron plasma sheet on the duskside and (2) that they may have been related to the arrival on the duskside of a substorm-associated westward traveling surge-like structure. The observations appear to be consistent with the development of a shear flow and/or ballooning type of instability at the plasmapause driven by intense SAPS-associated shear flows.

Magnetospheric substorms—definition and signatures

by John Foster and R. McPherron

Journal of Geophysical Research, 1980

For many years, researchers have utilized definitions of the substorm phenomenon that are not con... more For many years, researchers have utilized definitions of the substorm phenomenon that are not consistent among one another, and this has created great difficulties in comparing the results reported in the literature by the various researchers. In August 1978, nine magnetospheric physicists active in the field of substorm research met in Victoria, British Columbia, Canada, to attempt to reach a consensus on an acceptable definition for a magnetospheric substorm. This paper reports the agreements reached at the Victoria workshop and presents an operational definition of the magnetospheric substorm and a critique of the various signatures by which researchers can identify the time sequence and spatial extent of the substorm.

High-latitude convection: Comparison of a simple model with incoherent scatter observations

Journal of Geophysical Research, 1980

We have compared a simple model of predictions of plasma flow patterns with plasma convection at ... more We have compared a simple model of predictions of plasma flow patterns with plasma convection at high latitudes with data observations by the incoherent scatter radar obtained from simultaneous measurements made by technique. Of particular interest are the incoherent scatter facilities at Chatanika, differences of plasma flow predicted by the model Alaska and Millstone Hill, Massachusetts in June at different

Multiradar observations of the polar tongue of ionization

Journal of Geophysical Research, 2005

1] We present a global view of large-scale ionospheric disturbances during the main phase of a ma... more 1] We present a global view of large-scale ionospheric disturbances during the main phase of a major geomagnetic storm. We find that the low-latitude, auroral, and polar latitude regions are coupled by processes that redistribute thermal plasma throughout the system. For the large geomagnetic storm on 20 November 2003, we examine data from the high-latitude incoherent scatter radars at Millstone Hill, Sondrestrom, and EISCAT Tromso, with SuperDARN HF radar observations of the high-latitude convection pattern and DMSP observations of in situ plasma parameters in the topside ionosphere. We combine these with north polar maps of stormtime plumes of enhanced total electron content (TEC) derived from a network of GPS receivers. The polar tongue of ionization (TOI) is seen to be a continuous stream of dense cold plasma entrained in the global convection pattern. The dayside source of the TOI is the plume of storm enhanced density (SED) transported from low latitudes in the postnoon sector by the subauroral disturbance electric field. Convection carries this material through the dayside cusp and across the polar cap to the nightside where the auroral F region is significantly enhanced by the SED material. The three incoherent scatter radars provided full altitude profiles of plasma density, temperatures, and vertical velocity as the TOI plume crossed their different positions, under the cusp, in the center of the polar cap, and at the midnight oval/polar cap boundary. Greatly elevated F peak density (>1.5E12 m À3 ) and low electron and ion temperatures ($2500 K at the F peak altitude) characterize the SED/TOI plasma observed at all points along its high-latitude trajectory. For this event, SED/TOI F region TEC (150-1000 km) was $50 TECu both in the cusp and in the center of the polar cap. Large, upward directed fluxes of O+ (>1.E14 m À2 s À1 ) were observed in the topside ionosphere from the SED/TOI plume within the cusp.

Significant depletions of the ionospheric plasma density at middle latitudes: A possible signature of equatorial spread F bubbles near the plasmapause

Journal of Geophysical Research, 2007

Plasma density irregularities in the equatorial F region ionosphere are generally called equatori... more Plasma density irregularities in the equatorial F region ionosphere are generally called equatorial spread F (ESF). Large-scale plasma bubbles associated with ESF processes are generated in the bottomside F region and penetrate the F peak to the topside F region. It is still not fully understood how high ESF bubbles can reach. In this paper, we present the measurements of