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Energetics of small electron acceleration episodes in the solar corona from radio noise storm observations  

Prasad Subramanian   Submitted: 2018-05-21 23:23

Observations of radio noise storms can act as sensitive probes of nonthermal electrons produced in small acceleration events in the solar corona. We use data from noise storm episodes observed jointly by the Giant Metrewave Radio Telescope (GMRT) and the Nançay Radioheliograph (NRH) to study characteristics of the nonthermal electrons involved in the emission. We find that the electrons carry 1021 to 1024 erg/s, and that the energy contained in the electrons producing a representative noise storm burst ranges from 1020 to 1023 ergs. These results are a direct probe of the energetics involved in ubiquitous, small-scale electron acceleration episodes in the corona, and could be relevant to a nanoflare-like scenario for coronal heating.

Authors: Tomin James, Prasad Subramanian
Projects: None

Publication Status: To appear in the Monthly Notices of the Royal Astronomical Society
Last Modified: 2018-05-23 11:07
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Was the cosmic ray burst detected by the GRAPES-3 on 22 June 2015 caused by transient weakening of geomagnetic field or by an interplanetary anisotropy?  

Prasad Subramanian   Submitted: 2018-03-29 00:18

The GRAPES-3 muon telescope in Ooty, India had claimed detection of a 2 hour (h) high-energy (∼20 GeV) burst of galactic cosmic-rays (GCRs) through a >50σ surge in GeV muons, was caused by reconnection of the interplanetary magnetic field (IMF) in the magnetosphere that led to transient weakening of Earth's magnetic shield. This burst had occurred during a G4-class geomagnetic storm (storm) with a delay of 12h relative to the coronal mass ejection (CME) of 22 June 2015 (Mohanty et al., 2016). However, recently a group interpreted the occurrence of the same burst in a subset of 31 neutron monitors (NMs) to have been the result of an anisotropy in interplanetary space (Evenson et al., 2017) in contrast to the claim in (Mohanty et al., 2016). A new analysis of the GRAPES-3 data with a fine 10.6∘ angular segmentation shows the speculation of interplanetary anisotropy to be incorrect, and offers a possible explanation of the NM observations. The observed 28 minutes (min) delay of the burst relative to the CME can be explained by the movement of the reconnection front from the bow shock to the surface of Earth at an average speed of 35 km s-1, much lower than the CME speed of 700 km s-1. This measurement may provide a more accurate estimate of the start of the storm.

Authors: P.K. Mohanty, K.P. Arunbabu, T. Aziz, S.R. Dugad, S.K. Gupta, B. Hariharan, P. Jagadeesan, A. Jain, S.D. Morris, P.K. Nayak, P.S. Rakshe, K. Ramesh, B.S. Rao, M. Zuberi, Y. Hayashi, S. Kawakami, P. Subramanian, S. Raha, S. Ahmad, A. Oshima, S. Shibata, H. Kojima
Projects: None

Publication Status: To appear in Phys. Rev D
Last Modified: 2018-03-29 09:41
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Small electron acceleration episodes in the solar corona  

Prasad Subramanian   Submitted: 2017-06-14 00:06

We study the energetics of nonthermal electrons produced in small acceleration episodes in the solar corona. We carried out an extensive survey spanning 2004-2015 and shortlisted 6 impulsive electron events detected at 1 AU that was not associated with large solar flares(GOES soft X-ray class > C1) or with coronal mass ejections. Each of these events had weak, but detectable hard Xray (HXR) emission near the west limb, and were associated with interplanetary type III bursts. In some respects, these events seem like weak counterparts of "cold/tenuous" flares. The energy carried by the HXR producing electron population was ≈1023 - 1025 erg, while that in the corresponding population detected at 1 AU was ≈1024-1025 erg. The number of electrons that escape the coronal acceleration site and reach 1 AU constitute 6 % to 148 % of those that precipitate downwards to produce thick target HXR emission.

Authors: Tomin James, Prasad Subramanian, Eduard P Kontar
Projects: RHESSI

Publication Status: Accepted, Monthly Notices of the Royal Astronomical Society
Last Modified: 2017-06-14 10:01
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Amplitude of solar wind density turbulence from 10-45 R⊙  

Prasad Subramanian   Submitted: 2016-11-15 00:03

We report on the amplitude of the density turbulence spectrum (C2N) and the density modulation index (δN/N) in the solar wind between 10 and 45R⊙. We derive these quantities using a structure function that is observationally constrained by occultation observations of the Crab nebula made in 2011 and 2013 and similar observations published earlier. We use the most general form of the structure function, together with currently used prescriptions for the inner/dissipation scale of the turbulence spectrum. Our work yields a comprehensive picture of a) the manner in which C2N and δN/N vary with heliocentric distance in the solar wind and b) of the solar cycle dependence of these quantities.

Authors: K. Sasikumar Raja, Madhusudan Ingale, R. Ramesh, Prasad Subramanian, P. K. Manoharan, P. Janardhan
Projects: None

Publication Status: Accepted for publication, JGR
Last Modified: 2016-11-16 08:45
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CME propagation: Where does the solar wind drag take over?  

Prasad Subramanian   Submitted: 2015-07-21 00:23

We investigate the Sun-Earth dynamics of a set of eight well observed solar coronal mass ejections (CMEs) using data from the STEREO spacecraft. We seek to quantify the extent to which momentum coupling between these CMEs and the ambient solar wind (i.e., the aerodynamic drag) influences their dynamics. To this end, we use results from a 3D flux rope model fit to the CME data. We find that solar wind aerodynamic drag adequately accounts for the dynamics of the fastest CME in our sample. For the relatively slower CMEs, we find that drag-based models initiated below heliocentric distances ranging from 15 to 50 R⊙ cannot account for the observed CME trajectories. This is at variance with the general perception that the dynamics of slow CMEs are influenced primarily by solar wind drag from a few R⊙ onwards. Several slow CMEs propagate at roughly constant speeds above 15-50 R⊙. Drag-based models initiated above these heights therefore require negligible aerodynamic drag to explain their observed trajectories.

Authors: Nishtha Sachdeva, Prasad Subramanian, Robin Colaninno, Angelos Vourlidas
Projects: STEREO

Publication Status: Accepted, ApJ
Last Modified: 2015-07-22 14:54
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The structure of solar radio noise storms  

Prasad Subramanian   Submitted: 2014-12-30 06:51

The Nançay Radioheliograph (NRH) routinely produces snapshot images of the full sun at frequencies between 150 and 450 MHz, with typical resolution 3 arcmin and time cadence 0.2 s. Combining visibilities from the NRH and from the Giant Meterwave Radio Telescope (GMRT) allows us to produce images of the sun at 236 or 327 MHz, with a large FOV, high resolution and time cadence. We seek to investigate the structure of noise storms (the most common non-thermal solar radio emission). We focus on the relation of position and altitude of noise storms with the observing frequency and on the lower limit of their sizes. We present results for noise storms on four days. The results consist of an extended halo and of one or several compact cores with relative intensity changing over a few seconds. We found that core sizes can be almost stable over one hour, with a minimum in the range 31-35 arcsec (less than previously reported) and can be stable over one hour. The heliocentric distances of noise storms are ∼1.20 and 1.35 R⊙ at 432 and 150 MHz, respectively. Regions where storms originate are thus much denser than the ambient corona and their vertical extent is found to be less than expected from hydrostatic equilibrium. The smallest observed sizes impose upper limits on broadening effects due to scattering on density inhomogeneities in the low and medium corona and constrain the level of density turbulence in the solar corona. It is possible that scatter broadening has been overestimated in the past, and that the observed sizes cannot only be attributed to scattering. The vertical structure of the noise storms is difficult to reconcile with the classical columnar model.

Authors: Claude Mercier, Prasad Subramanian, Gilbert Chambe, P. Janardhan
Projects: None

Publication Status: Accepted, Astronomy and Astrophysics
Last Modified: 2014-12-31 13:43
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Coronal turbulence and the angular broadening of radio sources - the role of the structure function  

Prasad Subramanian   Submitted: 2014-12-22 21:43

The amplitude of density turbulence in the extended solar corona, especially near the dissipation scale, impinges on several problems of current interest. Radio sources observed through the turbulent solar wind are broadened due to refraction by and scattering off density inhomogeneities, and observations of scatter broadening are often employed to constrain the turbulence amplitude. The extent of such scatter broadening is usually computed using the structure function, which gives a measure of the spatial correlation measured by an interferometer. Most such treatments have employed analytical approximations to the structure function that are valid in the asymptotic limits s \gg li or s ≪ li, where s is the interferometer spacing and li is the inner scale of the density turbulence spectrum. We instead use a general structure function (GSF) that straddles these regimes, and quantify the errors introduced by the use of these approximations. We have included the effects of anisotropic scattering for distant cosmic sources viewed through the solar wind at small elongations. We show that the regimes where the GSF predictions are more accurate than those of the asymptotic expressions are not only of practical relevance, but are where inner scale effects influence estimates of scatter broadening. Taken together, we argue that the GSF should henceforth be used for scatter broadening calculations and estimates of turbulence amplitudes in the solar corona and solar wind.

Authors: M. Ingale, Prasad Subramaian, Iver Cairns
Projects: None

Publication Status: Accepted, Monthly Notices of the Royal Astronomical Society
Last Modified: 2014-12-23 14:49
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Self-similar expansion of solar coronal mass ejections: implications for Lorentz self-force driving  

Prasad Subramanian   Submitted: 2014-06-03 00:24

We examine the propagation of several CMEs with well-observed flux rope signatures in the field of view of the SECCHI coronagraphs aboard the STEREO satellites using the GCS fitting method of Thernisien, Vourlidas & Howard (2009). We find that the manner in which they propagate is approximately self-similar; i.e., the ratio (\kappa) of the flux rope minor radius to its major radius remains approximately constant with time. We use this observation of self-similarity to draw conclusions regarding the local pitch angle (\gamma) of the flux rope magnetic field and the misalignment angle (χ) between the current density {\mathbf J} and the magnetic field {\mathbf B}. Our results suggest that the magnetic field and current configurations inside flux ropes deviate substantially from a force-free state in typical coronagraph fields of view, validating the idea of CMEs being driven by Lorentz self-forces.

Authors: Prasad Subramanian, K. P. Arunbabu, Angelos Vourlidas, Adwiteey Mauriya
Projects: STEREO

Publication Status: Accepted, ApJ
Last Modified: 2014-06-04 13:45
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High rigidity Forbush decreases: due to CMEs or shocks?  

Prasad Subramanian   Submitted: 2013-04-25 10:20

We seek to identify the primary agents causing Forbush decreases (FDs) observed at the Earth in high rigidity cosmic rays. In particular, we ask if such FDs are caused mainly by coronal mass ejections (CMEs) from the Sun that are directed towards the Earth, or by their associated shocks. We use the muon data at cutoff rigidities ranging from 14 to 24 GV from the GRAPES-3 tracking muon telescope to identify FD events. We select those FD events that have a reasonably clean profile, and can be reasonably well associated with an Earth-directed CME and its associated shock. We employ two models: one that considers the CME as the sole cause of the FD (the CME-only model) and one that considers the shock as the only agent causing the FD (the shock-only model). We use an extensive set of observationally determined parameters for both these models. The only free parameter in these models is the level of MHD turbulence in the sheath region, which mediates cosmic ray diffusion (into the CME, for the CME-only model and across the shock sheath, for the shock-only model). We find that good fits to the GRAPES-3 multi-rigidity data using the CME-only model require turbulence levels in the CME sheath region that are only slightly higher than those estimated for the quiet solar wind. On the other hand, reasonable model fits with the shock-only model require turbulence levels in the sheath region that are an order of magnitude higher than those in the quiet solar wind. This observation naturally leads to the conclusion that the Earth-directed CMEs are the primary contributors to FDs observed in high rigidity cosmic rays.

Authors: Arun Babu, H. M. Antia, S. R. Dugad, S. K. Gupta, Y. Hayashi, S. Kawakami, P. K. Mohanty, T. Nonaka, A. Oshima, P. Subramanian
Projects: None

Publication Status: Accepted for publication in Astronomy and Astrophysics
Last Modified: 2013-04-26 10:15
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Can solar wind viscous drag account for CME deceleration?  

Prasad Subramanian   Submitted: 2012-09-12 23:57

The forces acting on solar Coronal Mass Ejections (CMEs) in the interplanetary medium have been evaluated so far in terms of an empirical drag coefficient C m D sim 1 that quantifies the role of the aerodynamic drag experienced by a typical CME due to its interaction with the ambient solar wind. We use a microphysical prescription for viscosity in the turbulent solar wind to obtain an analytical model for the drag coefficient C m D. This is the first physical characterization of the aerodynamic drag experienced by CMEs. We use this physically motivated prescription for C m D in a simple, 1D model for CME propagation to obtain velocity profiles and travel times that agree well with observations of deceleration experienced by fast CMEs.

Authors: Prasad Subramanian (IISER Pune, India), Alejandro Lara, Andrea Borgazzi (UNAM, Mexico)
Projects: None

Publication Status: Accepted for publication in the Geophysical Research Letters
Last Modified: 2012-09-13 10:14
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Constraints on coronal turbulence models from source sizes of noise storms at 327 MHz  

Prasad Subramanian   Submitted: 2010-12-17 05:19

We seek to reconcile observations of small source sizes in the solar corona at 327 MHz with predictions of scattering models that incorporate refractive index effects, inner scale effects and a spherically diverging wavefront. We use an empirical prescription for the turbulence amplitude CN2(R) based on VLBI observations by Spangler and coworkers of compact radio sources against the solar wind for heliocentric distances R approx 10-50 Rodot. We use the Coles & Harmon model for the inner scale li(R), that is presumed to arise from cyclotron damping. In view of the prevalent uncertainty in the power law index that characterizes solar wind turbulence at various heliocentric distances, we retain this index as a free parameter. We find that the inclusion of spherical divergence effects suppresses the predicted source size substantially. We also find that inner scale effects significantly reduce the predicted source size. An important general finding for solar sources is that the calculations substantially underpredict the observed source size. Three possible, non-exclusive, interpretations of this general result are proposed. First and simplest, future observations with better angular resolution will detect much smaller sources. Consistent with this, previous observations of small sources in the corona at metric wavelengths are limited by the instrument resolution. Second, the spatially-varying level of turbulence CN2(R) is much larger in the inner corona than predicted by straightforward extrapolation Sunwards of the empirical prescription, which was based on observations between 10-50 Rodot. Either the functional form or the constant of proportionality could be different. Third, perhaps the inner scale is smaller than the model, leading to increased scattering.

Authors: Prasad Subramanian (IISER Pune, India), Iver Cairns (U. Sydney, Australia)
Projects: None

Publication Status: Accepted for publication in the Journal of Geophysical Research (Space Physics)
Last Modified: 2010-12-17 09:41
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Driving Currents for Flux Rope Coronal Mass Ejections  

Prasad Subramanian   Submitted: 2008-10-23 22:38

We present a method for measuring electrical currents enclosed by flux rope structures that are ejected within solar coronal mass ejections (CMEs). Such currents are responsible for providing the Lorentz self-force that propels CMEs. Our estimates for the driving current are based on measurements of the propelling force obtained using data from the LASCO coronagraphs aboard the SOHO satellite. We find that upper limits on the currents enclosed by CMEs are typically around 1010 Amperes. We estimate that the magnetic flux enclosed by the CMEs in the LASCO field of view is a few imes 1021 Mx.

Authors: Prasad Subramanian, Angelos Vourlidas
Projects: SoHO-LASCO

Publication Status: Accepted for publication in the Astrophysical Journal
Last Modified: 2008-10-24 06:47
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Forbush decreases and turbulence levels at CME fronts  

Prasad Subramanian   Submitted: 2008-10-16 22:17

We seek to estimate the average level of MHD turbulence near coronal mass ejection (CME) fronts as they propagate from the Sun to the Earth. We examine the cosmic ray data from the GRAPES-3 tracking muon telescope at Ooty, together with the data from other sources for three well observed Forbush decrease events. Each of these events are associated with frontside halo Coronal Mass Ejections (CMEs) and near-Earth magnetic clouds. In each case, we estimate the magnitude of the Forbush decrease using a simple model for the diffusion of high energy protons through the largely closed field lines enclosing the CME as it expands and propagates from the Sun to the Earth. We use estimates of the cross-field diffusion coefficient Dperp derived from published results of extensive Monte Carlo simulations of cosmic rays propagating through turbulent magnetic fields. Our method helps constrain the ratio of energy density in the turbulent magnetic fields to that in the mean magnetic fields near the CME fronts. This ratio is found to be sim 2% for the 11 April 2001 Forbush decrease event, sim 6% for the 20 November 2003 Forbush decrease event and sim 249% for the much more energetic event of 29 October 2003.

Authors: Prasad Subramanian, H. M. Antia, S. R. Dugad, U. D. Goswami, S. K. Gupta, Y. Hayashi, N. Ito, S. Kawakami, H. Kojima, P. K. Mohanty, P. K. Nayak, T. Nonaka, A. Oshima, K. Sivaprasad, H. Tanaka, S. C. Tonwar
Projects: None

Publication Status: Accepted for publication in Astronomy & Astrophysics
Last Modified: 2008-10-17 06:51
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An evaluation of possible mechanisms for anomalous resistivity in the solar corona  

Prasad Subramanian   Submitted: 2007-06-07 23:00

A wide variety of transient events in the solar corona seem to require explanations that invoke fast reconnection. Theoretical models explaining fast reconnection often rely on enhanced resistivity. We start with data derived from observed reconnection rates in solar flares and seek to reconcile them with the chaos-induced resistivity model of Numata & Yoshida (2002) and with resistivity arising out of the kinetic Alfvén wave (KAW) instability. We find that the resistivities arising from either of these mechanisms, when localized over lengthscales of the order of an ion skin depth, are capable of explaining the observationally mandated Lundquist numbers.

Authors: K. A. P. Singh, Prasad Subramanian
Projects: None

Publication Status: Accepted, Solar Physics
Last Modified: 2007-06-08 11:45
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Electron acceleration in solar noise storms  

Prasad Subramanian   Submitted: 2007-03-27 00:38

We present an up-to-date review of the physics of electron acceleration in solar noise storms. We describe the observed characteristics of noise storm emission, emphasizing recent advances in imaging observations. We briefly describe the general method ology of treating particle acceleration problems and apply it to the specific problem of electron acceleration in noise storms. We dwell on the issue of the efficiency of the overall noise storm emission process and outline open problems in this area.

Authors: Prasad Subramanian
Projects: None

Publication Status: Review article, to appear in Asian J. of Physics, 2007
Last Modified: 2007-03-27 12:33
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Electron acceleration in a post-flare decimetric continuum source  

Prasad Subramanian   Submitted: 2007-03-25 23:04

Aims: To calculate the power budget for electron acceleration and the efficiency of the plasma emission mechanism in a post-flare decimetric continuum source. Methods: We have imaged a high brightness temperature (sim 109K) post-flare source at 1060 MHz with the Giant Metrewave Radio Telescope (GMRT). We use information from these images and the dynamic spectrum from the Hiraiso spectrograph together with the theoretical method described in Subramanian & Becker (2006) to calculate the power input to the electron acceleration process. The method assumes that the electrons are accelerated via a second-order Fermi acceleration mechanism. Results: We find that the power input to the nonthermal electrons is in the range 3 imes 1025-1026 erg/s. The efficiency of the overall plasma emission process starting from electron acceleration and culminating in the observed emission could range from 2.87 imes 10-9 to 2.38 imes 10-8.

Authors: Prasad Subramanian, S. M. White, M. Karlický, R. Sych, H. S. Sawant, S. Ananthakrishnan
Projects: None

Publication Status: Accepted for publication, Astronomy and Astrophysics
Last Modified: 2007-03-26 11:22
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Energetics of Solar Coronal Mass Ejections  

Prasad Subramanian   Submitted: 2007-01-08 21:39

Aims: To investigate if solar coronal mass ejections are driven mainly by coupling to the ambient solar wind, or through the release of internal magnetic energy. Methods: We examine the energetics of 39 flux-rope like coronal mass ejections (CMEs) from the Sun using data in the distance range sim 2-20 R{odot} from the Large Angle Spectroscopic Coronograph (LASCO) aboard the Solar and Heliospheric Observatory (SOHO). This comprises a complete sample of the best examples of flux-rope CMEs observed by LASCO in 1996-2001. Results: We find that 69% of the CMEs in our sample experience a clearly identifiable driving power in the LASCO field of view. For these CMEs which are driven, we examine if they might be deriving most of their driving power by coupling to the solar wind. We do not find conclusive evidence in favor of this hypothesis. On the other hand, we find that their internal magnetic energy is a viable source of the required driving power. We have estimated upper and lower limits on the power that can possibly be provided by the internal magnetic field of a CME. We find that, on the average, the lower limit on the available magnetic power is around 74% of what is required to drive the CMEs, while the upper limit can be as much as an order of magnitude larger.

Authors: Prasad Subramanian (1), Angelos Vourlidas (2) ((1) Indian Institute of Astrophysics, Bangalore, India; (2) Naval Research Laboratory, Washington, DC, USA)
Projects: SoHO-LASCO

Publication Status: Accepted for publication in Astronomy and Astrophysics
Last Modified: 2007-01-08 22:20
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Further constraints on electron acceleration in solar noise storms  

Prasad Subramanian   Submitted: 2006-02-28 22:56

We reexamine the energetics of nonthermal electron acceleration in solar noise storms. A new result is obtained for the minimum nonthermal electron number density required to produce a Langmuir wave population of sufficient intensity to power the noise storm emission. We combine this constraint with the stochastic electron acceleration formalism developed by Subramanian & Becker (2005) to derive a rigorous estimate for the efficiency of the overall noise storm emission process, beginning with nonthermal electron acceleration and culminating in the observed radiation. We also calculate separate efficiencies for the electron acceleration - Langmuir wave generation stage and the Langmuir wave - noise storm production stage. In addition, we obtain a new theoretical estimate for the energy density of the Langmuir waves in noise storm continuum sources.

Authors: Prasad Subramanian, Peter A. Becker
Projects: None

Publication Status: Accepted for publication in Solar Physics
Last Modified: 2006-02-28 22:56
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Combining visibilities from the Giant Meterwave Radio Telescope and the Nançay Radio Heliograph: High dynamic range snapshot images of the solar corona at 327 MHz  

Prasad Subramanian   Submitted: 2005-08-31 23:42

We report first results from an ongoing program of combining visibilities from the Giant Meterwave Radio Telescope (GMRT) and the Nançay Radio Heliograph (NRH) to produce composite snapshot images of the sun at meter wavelengths. We describe the data processing, including a specific multi-scale CLEAN algorithm. We present results of a) simulations for two models of the sun at 327 MHz, with differing complexity b) observations of a complex noise storm on the sun at 327 MHz on Aug 27 2002. Our results illustrate the capacity of this method to produce high dynamic range snapshot images when the solar corona has structures with scales ranging from the image resolution of 49'' to the size of the whole sun. We find that we cannot obtain reliable snapshot images for complex objects when the visibilities are sparsely sampled.

Authors: Claude Mercier (1), Prasad Subramanian (2), Alain Kerdraon (1), Monique Pick (1), S. Ananthakrishnan (3), P. Janardhan (4) ((1) Obs. Paris, Meudon, France, (2) IUCAA, Pune, India, (3) NCRA-TIFR, Pune, India, (4) PRL, Ahmedabad, India)
Projects: None

Publication Status: Accepted for publication in Astronomy & Astrophysics
Last Modified: 2005-08-31 23:42
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Energetics of Coronal Mass Ejections  

Prasad Subramanian   Submitted: 2005-02-07 05:51

We examine the energetics of the best examples of flux-rope CMEs observed by LASCO in 1996-2001. We find that 69% of the CMEs in our sample experience a driving power in the LASCO field of view. For these CMEs which are driven, we examine if they might be deriving most of their driving energy by coupling to the solar wind. We do not find conclusive evidence to support this hypothesis. We adopt two different methods to estimate the energy that can possibly be released by the internal magnetic fields of the CMEs. We find that the internal magnetic fields are a viable source of driving power for these CMEs.

Authors: Prasad Subramanian (IUCAA, Pune, India), Angelos Vourlidas (NRL, Washington, DC)
Projects: Soho-LASCO

Publication Status: To appear in proceedings of IAU Symposium 226, Coronal and Stellar Mass Ejections, Sept 13-17 2004, Beijing
Last Modified: 2005-02-07 05:51
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Abstracts by Author
Energetics of small electron acceleration episodes in the solar corona from radio noise storm observations
Was the cosmic ray burst detected by the GRAPES-3 on 22 June 2015 caused by transient weakening of geomagnetic field or by an interplanetary anisotropy?
Small electron acceleration episodes in the solar corona
Amplitude of solar wind density turbulence from 10--45 R⊙
CME propagation: Where does the solar wind drag take over?
The structure of solar radio noise storms
Coronal turbulence and the angular broadening of radio sources - the role of the structure function
Self-similar expansion of solar coronal mass ejections: implications for Lorentz self-force driving
High rigidity Forbush decreases: due to CMEs or shocks?
Can solar wind viscous drag account for CME deceleration?
Constraints on coronal turbulence models from source sizes of noise storms at 327 MHz
Driving Currents for Flux Rope Coronal Mass Ejections
Forbush decreases and turbulence levels at CME fronts
An evaluation of possible mechanisms for anomalous resistivity in the solar corona
Electron acceleration in solar noise storms
Electron acceleration in a post-flare decimetric continuum source
Energetics of Solar Coronal Mass Ejections
Further constraints on electron acceleration in solar noise storms
Combining visibilities from the Giant Meterwave Radio Telescope and the Nancay Radio Heliograph: High dynamic range snapshot images of the solar corona at 327 MHz
Energetics of Coronal Mass Ejections
Noise storm continua: power estimates for electron acceleration
Giant Meterwave Radio Telescope observations of an M2.8 flare: insights into the initiation of a flare-coronal mass ejection event
Noise storm continua: power estimates for electron acceleration
The Relationship of Coronal Mass Ejections to Streamers

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